Why don’t we ban Glyphosate? (Round Up)

Mendoza GL 2

Abandoned station as the plants reclaim…

There’s been a lot of publicity surrounding the herbicide Glyphosate, the main ingredient in Round Up. A recent court case determined that it can cause cancer. It has also been found in streams and some water supplies. The media have been vocal in the dangers of this terrible chemical, and people must be wondering: why hasn’t it been banned?

The problem is, there is pretty much no other effective herbicide to use.

As someone who’s worked for a number of gardening companies and in a number of large gardens, it’s been the only non-selective herbicide I’ve come across (non-selective means it kills all plants). However, I was aware a number of countries had banned it, so I was convinced there must be something else to use. It’s been bugging me for a while, so thought I’d do a bit of investigating.

Why Do We Need a Herbicide Anyway?

IMG_2783

Plants can grow anywhere

Naturally, when most people think about banning herbicides, they worry about the patios and paths in their gardens, but it’s a little more serious than that. It’s not surprising people think of plants as mostly well-behaved organisms, because that is how we keep them, manicured and contained. But plants have been colonising land since long before animals ever did, and they’re very good at it. If all humans suddenly vanished, it would only be a few years before plants had made headway in reclaiming roads and buildings.

Many plants don’t need a nice flowerbed in order to grow, plenty don’t need soil at all.

How plants take over a hostile space

First moss and liverworts grow on bare rock, then when they die their decomposing leaves provide a little bit of soil for slightly bigger plants, which have more tenacious roots that ease into cracks. Then they die and create more soil. Soon there is enough soil for plants with tougher roots to sprout, and the cracks widen further. Once there’s a perfect environment for invasive weeds to take hold, it can be only a few months before waist high clumps are sprouting up in great numbers. And this can happen anywhere, on railway tracks, pavements, roads, even through walls.

Buddleia GL

Buddleia growing in railway arch walls

When it comes to invasive weeds, Buddleia (Buddleia davidii) and Japanese knotweed (Fallopia japonica) are the biggest problems, and a problem that only Glyphosate solves. Whereas plants such as Himalayan Balsam (Impatiens grandulifera) and Skunk Cabbage (Lysichiton americanus) tend to be confined to wet areas, Buddleia and knotweed can and do grow anywhere. Buddleia can grow in walls, knotweed can break through concrete. These plants are kept in check by Glyphosate, and whole companies exist to remove them. I studied for my spray certficate with a couple of guys whose sole job it was to inject Japanese Knotweed with Glyphosate. Without chemical intervention, these tough innovative plants would take over, and soon they would affect the running of trains, and damage buildings and roads. Pulling them out acheives little. Pull Buddleia out of a wall and you’ll damage the wall. Pull knotweed out of the ground and you’ll cause more shoots to sprout in their place like a Hydra from Greek mythology. A solution needs to be tough.

How Have Countries Banned Glyphosate?

Whenever trouble with Glyphosate raises its head, the media talks of countries which have banned it, so why can’t we? Looking deeper into this leads to some interesting caveats to the bans. Although 14 countries are reported as having bans, few have an outright ban.

Some countries, such as Belgium and the Netherlands have restricted use (only for commercial use or to treat invasive weeds). Some are undergoing the slow process to find alternatives and intend a ban in a few years time (eg France). Bermuda started out with an outright ban, then relaxed the laws. Canada has banned it except in the case of invasive weeds.

A number of countries such as Saudi Arabia, Kuwait, Qatar, Bahrain, Oman and the United Arab Emirates have an outright ban. I haven’t been able to find out why, but maybe there is a large lower-wage workforce there, who will do the weeding by hand. There are certainly invasive weeds in the Middle East, although many are dependent on irrigation provided by humans, so that may be  a factor. (If anyone knows the reason, please email me at the address at the bottom of this blog and I’ll update).

Despite headlines calling for a ban, it looks like the solution is more complicated.

What are the alternatives?

Salt – this is often cited, however, Sodium Chlorate, a derivative of salt used as a herbicide, is banned in Europe. Using it on a few weeds in one garden isn’t such a big deal, but using large amounts on train tracks could be an environmental disaster. It depletes the ozone layer and is harmful to aquatic life. It’s also toxic to humans.

Vinegarwas used in Bristol to control weeds for a year. It was found to be not cost effective and not have such a long-lasting effect as Glyphosate. Personally, I’d be concerned at the environmental effect of throwing large quantities of vinegar around. Large quantities of anything that kills plants can cause environmental harm.

Handweeding – this is incredibly slow and isn’t practical on a large scale. It would mean shutting down roads and train tracks and new purpose-built machinery and a lot of cheap labour. Fine for private gardens though.

Mulching – useful in flower beds, but useless on paths and patios and won’t stop plants that grow out of walls or through buildings.

Steam weeding (sometimes called Heat Weeding) – this involves a machine that sprays out water at 99 degrees. I’ve used one, it is effective, although still in its infancy, so the machine is cumbersome and not very versatile yet. It’s being trialled mainly in Australia and Sweden. Given time, it’s one of the best options and there needs to be investment, plus government incentives to use it.

Fire – not setting fire to the weeds, but running a flame over them. Another good possibility. Not something I’ve used, but I can see how it would work on open ground. I don’t know the logistics of using it on buildings, but it’s a possible solution.

And Finally…

I’m concerned that this blog may come across like I’m resigned to chemical use and I really don’t want that. This is a beautiful world, we’ve been messing with it for a long time and we’re starting to feel the terrible consequences of that. So it’s time to grow up as a species and start taking better care of our surroundings. One way to do that is to reduce chemical use and work with nature in a sustainable and less intensive way. There will be ways to reduce and eventually get rid of Glyphosate, but in order to do that, we need to accept it’s not just a matter of banning one chemical and then moving onto another.

If anyone has any knowledge or ideas to add to this, then drop me a line at therealtetrapod at gmail dot com. Thank you!

Mendoza Glyphosate

Another picture of Mendoza station, just because…

 

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How to Make a Rainbow Rose

My first thought on seeing one of these was, how do they do that? Well, I think I’ve figured it out…

Rainbow rose

Picture credit: my mum

 

I bought a rainbow rose for my mum on Mother’s Day, I guessed she’d be as curious as me to know how they make them. After having a think and looking at the base of the stem it became clear.

A normal, wrong-coloured rose is created by simply putting the end of the stem in food colouring (mixed with water), the plant then sucks it up as it would normal water, and the colour spreads throughout the stem, leaves and flowers.

Lengthways section through a rainbow rose

Lengthways section through a flower stem

cross section rainbow rose stem

Cross section through a flower stem showing different colours inject into the xylem

For a mutli-coloured rose it takes more precision, but the idea is the same. A different coloured dye is injected into each of the xylem tubes, these are around the edge of the stem and take water through the plant. Because the xylem tubes stretch from one end of the plant to the other, and do not merge, the food colouring remains separate, all the way to the petals, so that each petal is flooded with a different colour.

The evidence for this is small dots of colour around the edge of the cut stem, where the dye was injected in.

RHS Level 3: Plant taxonomy, structure, and function

  1. Understand the Plant Kingdom and the taxonomic hierarchy.

1.1 Describe the major groups of the Plant Kingdom.

List the main groups within bryophytes, pteridophytes, gymnosperms and angiosperms.

This is quite an archaic way of grouping plants. The kingdom Plantae is usually divided into 10 divisions, listed below, with the groups in the syllabus in bold. Gymnosperms consists of Pinophyta, Cycadophyta and Ginkgophyta. Angiosperms = Magnoliophyta:

  • Anthocerotophyta – hornworts
  • Marchantiophyta – liverworts
  • Bryophyta – mosses
  • Lycopodiophyta – club and spike-mosses
  • Pteridophyta – ferns and horsetails
  • Gnetophyta – 3 extant genera of woody plants
  • Cycadophyta – cycads
  • Ginkgophyta – Ginkgo
  • Pinophyta/Coniferophyta – conifers
  • Magnoliophyta – flowering plants
divisions-for-rhs

Plant Characteristics

Describe and compare the structural and reproductive characteristics of: mosses, ferns, conifers and flowering plants in relation to their adaptation to terrestrial life.

DETAILS OF ALTERNATION OF GENERATIONS AND HAPLOID/DIPLOID STRUCTURES ARE NOT REQUIRED.

I’ve written about these four groups previously, the information about structural and reproductive characteristics is in the first two paragraphs of each blog

  1. Mosses
  2. Ferns
  3. Conifers
  4. Flowering Plants

Brief description of reproductive characteristics:

Bryophytes – have sporophyte and gametophyte stages. Gametophyte is dominant.

Pteridophytes – have sporophyte and gametophyte stages. Sporophyte is typical fern, gametophyte is small and rarely noticed.

Gymnosperm – have male and female cones. Male cones drop pollen which is carried by wind.

Angiosperm – have flowers that may be dioecious, monoecious or hermaphrodite. Usually wind or insect pollinated (but other methods of pollination exist).

1.2 Describe features of plant classification and nomenclature relevant to horticulture.

State the hierarchy of botanical units and explain how and when they are used.

To include: family, genus, species, subspecies, varietas, forma.

To include ONE NAMED plant example for EACH of the above terms showing how it is written.

Family

Have the ending -aceae (many family names were recently changed to conform to this). Plant families are usually named after the biggest or most well known genus in that family. eg Euphorbiaceae, the family that the genus Euphorbia is in.

Genus

Genus is a subdivision of family. The genus of a plant is used as the first part of its binomial name, and is always capitalised. It should be written in italics (or underlined). eg Euphorbia.

Species

Species is a subdivision of genus. The species of a plant is used as the second part of its binomial name and is never capitalised. It should be written in italics (or underlined). eg characias  (as in Euphorbia characias.)

Subspecies

Recommended abbreviation is subsp. but ssp. is sometimes used. Subspecies are written in small italics, but the word subsp. is not. A subdivision of species. Plants within different subspecies but within the same species are capable of interbreeding, but don’t due to geographical separation. eg Euphorbia characias subsp. wulfenii.

Varietas

A subdivision of species, similar to subspecies (and the two terms often overlap) however, different varieties within a species may geographically overlap, unlike subspecies. Recommended abbreviation is var. Varieties are written in italics, but var. is not. eg Malva alcea var. fastigiata.

Forma

If a plant shows uncharacteristic appearance of its species (such as habit or colour) then it can be known as a different form. These differences are usually due to environmental reasons and won’t be passed to the next generation. Recommended abbreviation is f. The form is written in italics, but f. is not. eg Vinca minor f. alba.

Explain the meaning and use of the terms: cultivar, Group, trade designation (selling name), Plant Breeders’ Rights, interspecific, intergeneric and graft hybrids, naming authority.

To include ONE NAMED plant example for EACH of the above terms, showing how it is written.

Cultivar: This is short for ‘cultivated variety’ and refers to plants that have been bred for their characteristics. The names are often chosen as a selling point, for example using somebody’s name, making them a good present for people of the same name. eg Clematis ‘Willy’ (note the cultivar name is capitalized, in single quotes and not italicized. Because of the complexity of cross breeding across species, the species of a cultivar is only sometimes used.)

Group: If several cultivars are similar, they can be grouped together to make customer selection easier. eg Lilium Darkest Red Group (note the group is capitalized, not italicized, and not in quotes.)

Trade designation: Cultivar names cannot be legally protected. If a plant breeder wishes to keep sole legal rights to a plant, then he/she uses a trade name. This a commercial synonym that is legally protected. eg Rosa FASCINATION = Rosa ‘Poulmax’. (note: the writing method for ‘Fascination’ changes, sometimes it is in quotes, like a cultivar; other times it is in square brackets. The correct notation is all in capitals, not italicized, not in quotes, often in a different font.)

Plant Breeders’ Rights: Breeders using a Trade designation have Plant Breeders’ Rights which are recognised internationally. If you own the rights to a cultivar, it cannot be bred by anyone else without your permission. If somebody buys one specimen of your cultivar, you still have exclusive rights to all propagation material of that plant: seeds, cuttings etc.

Interspecific, intergeneric and graft hybrids: Unlike with animals, plants can be bred across species and genera. Plants of different genera can, in some cases, be grafted together, occasionally this will lead to a mixing of cells where the scion and the rootstock meet, this is not a true hybrid. It is also known as a graft chimaera.

examples

  • Interspecific hybrid –  Mahonia × media (bred from Mahonia lomariifolia and Mahonia japonica, note the ‘x’ in the middle and new specific epithet.)
  • Intergeneric hybrid× Cupressocyparis leylandii (bred from Cupressus macrocarpa and Chamaecyparis nootkatensis, note the ‘x’ at the beginning and the genus which is a combination of the parents’).
  • Graft hybrid – +Laburnocytisus ‘Adamii’, (a graft hybrid between Laburnum and Cytisus, note the ‘+’ at the start and genus which is a combination of the parents’.) This graft contains flowers of Laburnum and Cytisus (ie both yellow and purple) but also flowers that are a pinky colour, a mix of the two.

Naming authority: The International Cultivation Registration Authority is a naming authority, responsible for seeing that cultivar names are not duplicated.

State the significance of the ICN (The International Code of Nomenclature for algae, fungi and plants) formerly ICBN (International Code of Botanical Nomenclature) and the ICNCP (International Code for Nomenclature for Cultivated Plants) in the naming of plants.

The ICN (The International Code of Nomenclature for algae, fungi and plants) A code that governs plant discoveries in the world – ensuring that plants aren’t given different names by different discoverers, or that already named plants aren’t given new names without reason.

International Code of Nomenclature website Contains complex set of rules to standardise naming and classification eg changing all plant families to end in -aceae, Compositae > Asteraceae.

ICNCP (International Code for Nomenclature for Cultivated Plants) – a code that governs the naming of newly created cultivars.

Cultivated Plant Code

(For more information about the latest ICNCP, there’s an interesting article on Gardening Wizards, here)

Explain the reasons for name changes: reclassification (scientific research, new discovery), changes in nomenclature (rule of priority), incorrect identification.

To include TWO NAMED plant examples for EACH.

Reclassification (scientific research, new discovery)

  1. With advances in DNA technology, African Acasias were found to not be related to Australian Acasias. Australian Acasias have kept their name, while African have become Vachellia or Senegalia.
  2. Coleus became Solenostemon, but was then found to be part of the Plectranthus genus. Plectranthus scutellarioides used to be Coleus blumei.

Rule of priority

This is where a plant is discovered to have been named previously, and its old name is found on record. When an existing name is discovered, the plant should revert to this name, but occasionally, if the new name is far more familiar it will be kept.

  1. Platanus ×acerifolia was the name of the London Plane, but this name was recorded in 1805 and it was discovered later that an earlier name of Platanus ×hispanica had been recorded in 1770. Therefore Platanus ×hispanica became the official name.
  2. Festuca subgenus Schedonorus was moved to the genus Lolium and its name became Lolium subgenus Schedonorus.

Incorrect identification

Sometimes a name change is due to a simple mistake, when one plant becomes mixed up with another.

  1. Archontophoenix cunninghamiana was for a long time incorrectly sold as Seaforthia elegans.
  2. Syzygium australe was often sold as Syzygium paniculatum

 Explain how plant names can indicate: plant origin, habitat, commemoration, colour, growth habit, leaf form.

To include TWO NAMED plant examples for EACH. 

It is often the plant species that indicates origin, colour etc, but not always (see below). The Latin will only refer to one characteristic (when Latin plant names were first used, botanists tried to include every characteristic, leading to ridiculously long names, then Linnaeus reduced it to two).

Plant origin: Mahonia japonica (Japan), Arum italicum (Italy)

Habitat: Clematis alpina (alpine plants), Pinus sylvestris (wood or forest)

Commemoration: Photinia fraseri (John Fraser1750-1811 nurseryman), Weigela (Christian Weigel 1749-1831 German botanist)

Growth: Briza maxima (large or largest), Vinca minor (smaller)

Habit: Cotoneaster horizontalis (growing horizontally), Phlomis fruticose (shrubby)

Leaf form: Acer palmatum (palmate leaves), Ilex aquifolium (pointed leaves)

Schachen Alpine Garden

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Schachen Landscape

Open four months of the year and accessible only on foot, the Schachen Alpine Garden contains plants from all over the world. As can be seen in the photos, Schachen is often foggy, and despite being surrounded by the Alps, we barely saw them.

Alpine plants have a few conditions in common no matter where they are from; they have to cope with extreme cold (Schachen is often covered with snow), a short growing season, high winds, and a lack of rain. Alpine plants are mostly small and low growing, this enables them to flower in the short time when the conditions are favourable and keep below the high winds.

Anthyllis vulneraria 2

Anthyllis vulneraria

 

A number of plants had an ability to repel water and hold it in droplets above the leaves, I think this is a way of protecting them when covered in snow, stopping the leaves from being damaged. (see photos below)

Due to the mix of rock types on the mountain, the soil is very varied, with alkaline and acid soils side by side. This means that acid loving and alkaline loving plants that would never normally grow together, do. For example, this wild Clematis alpina (alkaline) and pine tree (acid). (see below)

Clematis and pine

Clematis alpina growing on a pine

Many of the pine trees on the mountain are growing right out of the rock (see photos below). In autumn animals bury seeds in the rock to serve as food stores for the winter. Many of these seeds are forgotten, and then germinate.

The photo below is of an unusually shaped Campanula, nothing like the normal bell-shaped flower. Because of its shape it is known as devil’s claw.

Campanula

Devil’s Claw Campanula

Cows feed on the vegetation on the mountain. As it gets warmer, and the cows eat all the vegetation lower down, they are moved up higher. This can cause problems, because the cows will eat almost everything but Rheum (a genus containing rhubarb) because it is poisonous. As a result, the Rheum starts to take over, so there is a problem with this turning the mountain landscape into a monoculture. Rheum is the large-leaved plant in the photo below.

Mosses and lichens were in abundance in Schachen.

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Lichen growing on pine tree

Wild orchids grew on the mountain also.

My favourite two photos from the trip:

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Thistle flower

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Red spotted bug

landscape  5.JPG

Schachen Alpine Garden

 

 

Plant Families: Araceae (aka Aroids or Arums)

Zantedeschia Inflorescence

Zantedeschia Inflorescence

A Few Basic Facts

  • Aroids are monocots in the family Araceae (aka arum family), in the order Alismatales. Most other families in this order contain tropical or aquatic plants, eg Hydrocharis and Saggitaria.
  • Araceae has 104-107 genera. The largest genus is Anthurium with over 700 species.
  • Location: Latin American tropical regions have the greatest diversity of aroids, however, they can also be found in Asia and Europe. Australia has only one endemic species – Gymnostachys.
  • Habitat: Aroids can be aquatic (water), epiphytic (air) and terrestrial (ground). Most are tropical, but there are also arid and cold loving aroids.
  • Distinctive features: All have an inflorescence (a structure containing a group of smaller flowers) which consists of a spadix (always) and a spathe (sometimes).
OLYMPUS DIGITAL CAMERA

Aroid Flowers

  • Aroids can be hermaphrodite (each flower is both male and female), monoecious (male and female flowers on the same spadix) or dioecious (male and female flowers on completely different plants).
  • This family contains one of the largest flowers (Amorphophallus titanium, the titan arum) and the smallest (Wolffia, duckweed).
  • Some aroid leaf and inflorescence shapes:
Aroid Leaf Shapes

Aroid Leaf Shapes

Leaves

Aroid Leaves

Fruits

Aroid Fruits

Adaptations

Like many tropical families, aroids have evolved a number of adaptations to stay healthy and propagate. Some examples of adaptation:

  • The spathe protects the flowers and in some cases is used to trap insects for pollination. It is not a petal, but a modified leaf. Many spathes turn green and photosynthesize after flowering has finished.
  • Aroids have different types of roots adapted to their purpose. They have different adventitious roots  for climbing, attaching to rocks or taking in water.
  • Many tropical species have shiny leaves to deter the mosses and lichens that grow in abundance in the rainforest.
  • Smell is used by many species to attract pollinators. The smell of rotting meat, fungi and excrement is used for flies and beetles. Fragrant scents are used to attract bees.
  • In many species the spadix actually heats up and can reach 25°C, even in near freezing conditions. This increases the release of smells to attract pollinators. The heat also makes visiting insects more active.
  • Aroids that want to attract flies and beetles often have a warty, hairy, twisted appearance, with dark colours. This is to mimic the effect of dead animals, fungi or excrement.
  • In some species, leaves may change shape from juvenility to adulthood – changing from variegated to unvariegated, pale red to green, or altering the number of lobes of the leaf. Colour change may deter animals from feasting on the fresh young leaves by making them look less leaf-like.
  • Most species in Araceae have tubers or rhizomes, this means a damaged plant has the food storage and ability to grow new shoots from many points beneath the ground. Some aroids have other means of vegetatively propagating themselves, such as bubils and offsets.
  • A number of aroids are poisonous, some are edible. Aroids have evolved poisons in some species as protection. Those that are edible did not evolve to be eaten by us, rather we have evolved to be able to eat certain plants.

Reproduction

IMG_4023

Male and Female Flowers

Because many aroids are monoecious there is a danger of self-pollination. While self-pollination is easy (a guaranteed fertilisation), it leads to less genetic variety and less ability to adapt to changes in the environment. Aroids are particularly variable plants, in one small area of the Thai Peninsula 22 distinct varieties of the plant Aglaonaemia nitidum f. curtisii were found. However, in order to achieve this variation, the plant needs to cross pollinate reliably. It does this by being protogynous, meaning the female flowers on an inflorescence ripen first and then later male flowers produce pollen.

The Generic Process for Monoecious Aroids

A beetle, fly or bee (hopefully covered in pollen) is attracted by the scent given off by the heated spadix. The insect flies around inside the spathe, lands on the slippery surface and falls into the gap between the spadix and spathe. At this point only the female flowers are mature, and the  insect, made more active by heat from the spadix, moves about bumping into the flowers and depositing the pollen. Now, the insect has fulfilled the first part of its function, the aroid would like it to pick up pollen from the male flowers. However, the male flowers will not ripen for a day or so yet, so the insect needs to be held hostage. The slippery spathe ensures that the insect can’t escape, it is given sustenance in the form of nectar. Once the male flowers are ready and producing pollen, the slippery surface of the spathe breaks down, allowing the insect to escape. As it flies away it bumps into the male flowers, picking up more pollen to take to the next plant of the same species that it comes to.

Two Specific Examples of Monoecious Reproduction

Philodendron auminatissimum: Sometimes the pollinating insect can outstay its welcome, perhaps damaging flowers or laying eggs. This Philodendron has overcome the problem by shrinking the spathe after the male flowers have become active. This means that the beetle must leave or become crushed.

Arum nigrum: This arum doesn’t trap visiting flies, it merely confuses them. The hood of the spathe hangs over the spadix, obscuring the  sunlight, and there are translucent marking in the base of the spathe. When a visiting fly tries to escape, it heads for the light, but this just guides it deeper into the spathe. This leads to panicked and more active movement, ensuring pollination.

Arum nigrum

Arum nigrum

Reproduction in Other Aroids

In dioecious aroids the female flowers are found on a different plant to the male flowers, so a genetic mix is guaranteed. Not many aroids are dioecious, but a few species of Arisaema are.

A few aroids are even paradioecious and change gender to suit circumstances.

Hermaphrodite aroids are similar to monoecious ones, the male and female parts on each flower mature at different times so self pollination cannot occur.

Habitat

Arid

For the most part, arid aroids have not evolved the typical shrunken leaves and thickened cuticle of other desert plants. Instead they tend to grow under trees and bushes and at the base of rocks where a damp, shady microclimate allows them to survive. They have unusually lush foliage for arid plants. This would make them a target for being eaten, but they have dealt with this by producing harsh toxins and needles of calcium oxalate that pierce and poison the throats of animals. Animals know to stay well clear of aroids.

Some Examples

Dead Horse Arum

Heliocodicerous muscivorus

Heliocodicerous muscivorus: This is called the dead horse arum. It has an inflorescence 35cm long and wide. It grows in the shelter of rocks on a few islands on the Mediterranean. It is pollinated by either flies or beetles and grows where sea birds have their colonies at nesting time. Sea birds live in a mess of rotting fish and eggs, dead chicks and excrement, which attracts the flies/beetles. The arum must then compete with the smell of these, in order to attract those same insects for pollination. It mimics the dead not only in smell, but also by looking like the corpse of part of a horse, complete with tail. Visiting insects find themselves falling into where the ‘tail’ is and becoming trapped by the slippery walls. Many insects lay their eggs inside, although any maggots that hatch will likely starve to death. The insects are held for two to three days and are fed by nectar.

Note: It’s worth looking at photos of the dead horse arum, my painting doesn’t really do it justice.

Sauromatum venosum: This is the called the voodoo lily because it has the ability to flower without soil or water, using only the energy stored as starch in the corm. It smells rotten.

Stylochaeton lancifolius: This aroid has flowers and fruits half buried in the ground. I have been unable to find information about why this is. My suspicions are:

  1.  It is pollinated by animals that are close to the ground. This can be seen in Aspidistra flowers, pollinated by slugs and snails. The flowers grow on the ground, under the leaves.
  2. Being submerged provides a little protection, even if eaten or stepped on, the Stylochaeton still has half a flower remaining.
  3. The fruits are eaten by something small. Having eaten the fruit, the seeds can be dispersed in the faeces.
Stylochaeton lancifolia

Stylochaeton lancifolia

Tropical

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Rainforests are dense, shady, and teeming with aggressive life. Animals, plants, fungi and bacteria are locked in a constant arms race. Consequently aroids have developed strong poisons, shiny leaves and the ability to climb to cope with some of these problems. In the tropics, latitudinal diversity (a wider variety of organisms that occurs close to the equator) means that it may be many miles through dense forest between plants of the same species. For this reason, aroids use very strong, and often unpleasant, smells to attract the right kind of insect.

A tropical rainforest has distinct layers and aroids grow in each of these. There are terrestrial aroids growing in the ground and epiphytic ones that climb into the canopy.

Climbers and epiphytes have only aerial, adventitious roots. There are two types: those that are sensitive to light and make for dark crevices where they can grip, and those that are sensitive to gravity and hang down from the plant in order to soak up rain and humidity.

Terrestrial Examples

Deiffenbachia grows in the Americas, while Aglaonema is native to Asia, they are both highly variable, but virtually indistinguishable from one another. This is an example of convergent evolution. Both contain toxins as a defence; Deiffenbachia is commonly known as dumb cane, because the if eaten, it causes the throat to swell, so that speech is impossible.

Ag 2

Aglaonema and Deiffenbachia – both highly variable, but in similar ways

 

Amorphophallus: This is a genus of tropical and subtropical aroids, native to Asia, Africa and Australasia. They attract flies and beetles by giving off the smell of rotting meat. Unusually, Amorphophallus species only put out one leaf or one inflorescence at a time, one a year. The single leaf is highly divided.

IMG_4021

Some Amorphophallus inflorescences

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Single, highly divided leaf of Amorphophallus

Some species in this genus also have white patches on the stem, these are to mimic lichen growing on trees and serve to protect them from stampeding elephants. When tramping through the jungle elephants have learnt to avoid trees, which are usually covered in lichen. Amorphophallus would be very easily damaged by an elephant, so by looking a bit more like a tree they can fool the elephant into avoiding them.

IMG_0357

Lichen mimicking stem

Epiphytic Examples

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Monstera

Monstera: These are one of the few plants to have holes in their leaves. Recent research shows that leaves with holes benefit in shady areas because the light coming through the trees is often dappled. By having holes in their leaves, Monstera cover a larger area with the same amount of leaf (so the same amount of energy used to make it) as a smaller leaf without holes. This allows the plant to take advantage of any sunlight that gets through the canopy.

Anthurium punctatum: This is an aroid from Ecuador. It has formed a symbiotic relationship with ants. It has nectaries away from the flowers because it is not trying to attract pollinators, but protectors. The ants set up home in the Anthurium and guard it from animals and insects that may eat it. However, in this Anthurium the ants are particularly aggressive and keep away pollinators also. The ants also secrete an antibiotic substance called myrmiacin, which is antibiotic and protects the ants from moulds and bacteria that might cause disease. However, this substance prevents pollen tube formation needed for the plant to be fertilised. These two barriers to pollination mean that the species can only propagate itself vegetatively.

Philodendron: This is a diverse genus. Plants can be epiphytic, hemiephytic or (occasionally) terrestrial. Hemiepiphytic means that the plant spends part of its life-cycle as an epiphyte (in the air). It may start off on the ground and then wind its way up a tree, then let its original roots die back. Or it may start as a seedling in the branches of a tree and a root will trail its way to the ground.

Philodendron bipinnatifidum

Philodendron bipinnatifidum

Temperate Woodland

Arisarum proboscideum

Arisarum proboscideum

Arisarum proboscideum: aka the mouse plant. This is a woodland aroid, native to Spain and Italy. It has flowers like little mice. The ‘tails’ of these give off a mushroomy odor, that attract fungus gnats for pollination. The flowers have a spongy white appendage inside the spadix that looks like a mushroom to complete the deception. Fungus gnats often lay their eggs in the flowers, although the maggots won’t live to adulthood.

Aquatic

As I have blogged before, plants never evolved much in water. This means that all aquatic plants have evolved on land and then evolved again to cope with life in water. Some problems faced are – damage to flowers and leaves due to water currents, lack of access to pollinators, water blocking out light, lack of oxygen (leading to rotting roots), and the heaviness of water (800 times as dense as air) putting pressure on foliage.

Some solutions to problems:

  • Aerenchyma:  these are gas filled cavities that improve buoyancy and oxygenation.
  • Fish shaped foliage: these offer less resistance to water currents, so less damage occurs.
  • Larger surface area in relation to volume: ie filmy leaves. This increases photosynthesis  eg Cryptocoryne
  • Roots: These are not needed to transport water, since it can be taken in by all parts of the plant. However, roots are used to anchor the plant and stopped it being carried away by currents. eg Jasarum steyermarkii
  • Reproduction: Many aquatic aroids find it easier to spread vegetatively rather than by flowering, in order to avoid flowering problems.

An Example

Pistia stratiotes 2.JPG

Pistia stratiotes: This is the only floating aquatic aroid, growing in swampy deltas in India and West Africa. It is adapted to staying still in fast moving currents, and has found the balance between sinking and blowing away.  The inner tissues have aerenchyma and the outer surfaces are ridged, velvety and with dense covering of hairs. This makes it unable to sink, and water repellent. Feathery roots act as an anchor. It has tiny flowers in a protective hairy spathe.

Pistias form a dense mat on the surface of the water, and can create mats of 15m wide. This makes Pistia something of a weed, causing problems to the ecosystem because the water underneath is deprived of light.

However, Pistia is not only harmful, some ecological benefits:

  • The darkness caused by the Pistia mats has led to the evolution of blind elephantnose fish, which live beneath the mats. They hunt by electricity and have well developed brains and learning abilities.
  • Birds and animals often make the floating island their home.
  • Pistia can purify stagnant water.

 

Note: outdoor photos are mostly taken in Ecuador and indoor photos mostly from Wisley Gardens.

 

4. Understanding a range of specialist elements in the establishment of garden and urban plantings

This unit provides an understanding of the opportunities that exist for the use of specialist elements in the planting of a variety of gardens, including urban and amenity green spaces.

Understand the design principles and practices of using amenity bedding schemes.

1.1 Describe the design principles and practices used in amenity bedding schemes.

RHS description of bedding schemes

1.2 Review the spacing requirements of spring and summer bedding plants including bulbs.

Chionodoxa Blue Giant, Iris x germanica, Trillium cuneatum, Muscari armeniacum 5cm
Allium, Crocosmia ‘Lucifer’, Crocus, Hyacinthus orientalis ‘Blue Basket’, Narcissus poeticus, Tigridia 10cm
Lilium, Osteospermum jucundum, Celosia ‘Fresh Look Mix’, Lobelia erinus, Tagetes patula, Viola × wittrockiana, Lobularia maritima, Zinnia elegans ‘Dreamland Series’, Tulipa ‘Little Beauty’ 15cm
Fritillaria, Callistephus chinensis, Begonia semperflorens, Iberis sempervirens, Solenostemon scutellarioides ‘Wizard Series’, Centaurea cyanus, Dianthus barbatus, Rudbeckia hirta, Nicotiana sylvestris, Petunia hybrida, Phlox paniculata, Salvia roemeriana 20cm
Gaillardia ‘Arizona Sun’, Coreopsis grandiflora, Cosmos atrosanguineus, Dahlia ‘Garden Party’, Pelargonium x hortorum, Impatiens Accent Series, Capsicum annuum, Verbena ‘Lawrence Johnston’ 25cm
Alstroemeria , Canna, Musa basjoo 30cm

1.3 Produce a work schedule covering a 12-month period for a situation in 1.1.

For a summer bedding scheme

  • December – draw up plan and estimate numbers.
  • January – order plants; sow seeds under glass; take cuttings of overwintered perennials.
  • February – March – care for seedlings and cuttings; watering; P+D monitoring; potting on.
  • April – once chance of frost as passed, harden off plants.
  • Start of May – cultivate bedding area, treat perennial weeds and incorporate fertiliser.
  • May – mark out, place plants, plant, mulch, water.
  • June- October- water, weed, deadhead; feed in July, high potassium feed.
  • October – remove plants, pot up perennials to over-winter.

1.4 Describe specialist forms of bedding scheme, including carpet, three-dimensional and subtropical.

Carpet

Carpet bedding uses low growing, brightly coloured plants close to each other so that they knit together to create a carpet effect, it is intensive, using a lot of plants. It often involves using geometric designs, logos, words, coats of arms or floral clocks. Possible plants are rosette forming succulents like Echeveria or mat forming Alternanthera, also Saxifraga, Sedum and Sempervivum.

Three Dimensional

May use similar plants to carpet bedding since these can grow diagonally or vertically. A frame can be used in the shape of an animal or a pyramid, with plants then attached.

Some examples here

 Subtropical

Subtropical bedding uses exotic tender plants, usually with large or coloured foliage. Musa basjoo, Canna Tropicana, Solenostemon and Amaranthus caudatus are good examples of subtropical plants.

 2. Know the typical components of a range of specialist garden areas.

2.1 Describe the typical elements (including plants) of the following specialist areas: woodland; wildlife; sensory; low maintenance amenity; grass or steppe (prairie); and potager.

Woodland

A garden with a number of natural layers, canopy, understorey and ground level, the canopy is formed by trees, the understorey with shade tolerant shrubs and the ground level consists of low growing plants that either tolerate shade or make use of winter and spring when leaf cover is less dense and light can reach the plants.

Plants

Canopy – Fagus sylvatica or Quercus robur in natural woodland; or use more ornamental planting such as Betula pendula or Prunus serrula for trunks and winter interest.

On the woodland edge, where soil is neutral or acid and shade is dappled, it is possible to grow Acer palmatum, Hammamelis mollis, Rhododendron germania or Magnolia grandiflora.

Understorey – native shrubs like Ilex aquifolium, Sambucus nigra, Ruscus aculeatus. Lonicera periclymenum or Parthenocissus tricuspidata can grow through trees.

Ground layer – mainly spring bulbs – Galanthus nivalis, Allium caeruleum, Narcissus ‘Tete a Tete’, Anemone nemorosa. Perennials – Brunnera macrophylla, Pulmonaria vulgaris, Helleborus niger, Epimedium perralderianum, Geranium macrorrhizum, Athyrium niponicum var. pictum, Dryopteris filix-mas, Arum italicum, Colchicum autumnale.

Wildlife

A wildlife garden is not simply a garden allowed to grow wild, but one specifically designed to encourage wildlife. A wildlife garden uses plants that grow well in the allotted position and therefore don’t need environmentally unfriendly additions, such as peat. A wildlife garden provides as many habitats for wildlife as possible.

Some features

  • Large habitats – pond, hedgerow, stand of trees, green roves, dry stone wall of local stone.
  • Small habitats – insect habitat box (habitat wall), stag beetle loggery, pile of logs, beehive, climbers.
  • Cultural – not clearing away weeds unless they are invasive, leaving leaf and wood litter around, biological controls (no pesticides), allowing moss and lichen to grow on brick and wood of buildings.
  • Plants – naturalised (or native) and happy to grow in the environment, with nectar for bees, berries for birds.
  • Plant species – Colchicum autumnale, Viburnum bodnantense, Campanula spp., Cytisus scoparius, Eschscholzia californica, Nepeta cataria (mint), Helleborus spp., Aquilegia vulgaris, Agrostemma githago, Geranium phaeum, Hebe spp., Sedum spectabile, Mahonia spp., Phlox paniculata, Calendula officinalis, Primula vulgaris, Kniphofia spp., Rosa canina.

Sensory

Sensory gardens can be to help people with disabilities enjoy gardens more or to encourage children to interact with plants.

Features – wheel chair access, sculptures, sculpted handrails, scented plants and herbs, thornless roses, water features. Noise can be created with wind chimes, running water and noisy plants. Care needs to be given that plants and hard landscaping do not pose any possible health risk to vulnerable users.

Very good article here – tips for disabled gardeners.

A website selling products for a sensory garden – lots of interesting ideas for kids gardens (not plants).

Plants

Colour

  • Helianthus annuus – bright yellow flower that can grow up to 30cm height in a week.
  • Calendula officinalis – bright orange flowers.
  • Houttuynia cordata ‘Chameleon’ – three-toned foliage that smells of lemon.
  • Heuchera ‘Chocolate Ruffles’ – purple leaves with brown undersides and pale pink flowers.

Sound

  • Briza maxima, an annual grass, flowers rustle in the wind.
  • Nigella damascena – bright blue flowers which form puffy seed-heads that rattle .
  • Miscanthus oligostachyus ‘Nanus Variegatus’ – striped yellow and cream bamboo-like foliage, rustles in the breeze.
  • Phyllostachys nigra – rustling foliage and stems that knock together.

Touch

  • Stachys byzantina -silky foliage.
  • Salvia argentea – cotton down covers foliage.
  • Phlomis fruticosa – soft leaves and stems.
  • Sempervivum ‘Commander Hay’ – Leaves are rigid and fleshy to the touch.
  • Drosera capensis – sticky carnivorous plant

Smell

  • Helichrysum italicum – curry-scented leaves.
  • Lavandula angustifolia ‘Hidcote’ – scented flowers.
  • Cosmos atrosanguineus – chocolate coloured, vanilla scented flowers.
  • Lathyrus odoratus – scented flowers.
  • Melissa officinalis – lemon-scented leaves.

Taste

  • Mentha spicata – mint.
  • Rosmarinus officinalis – rosemary.
  • Tropaeolum majus – leaves can be used in salad.
  • Allium schoenoprasum – leaves can be used in salad.

Low maintenance

A low maintenance garden may be one on a housing estate where gardeners are only employed to come a few times a year or for a private household where the owners don’t have much time to work in the garden. Disadvantages are that the gardens can be a little uninspired.

  • Grass – do without, reduce, have simple lawn shape (sweeping curves/minimal trees), use mowing strip to save time strimming.
  • Borders – ground cover or drought resistant shrubs, slow growing plants, 65-70% evergreen, bark chip to minimise weeding, species roses (don’t need deadheading or treating for disease).
  • Avoid containers.
  • Install automatic watering.
  • Minimal planting – gravel garden.

Plants

  • Grasses – Carex flagellifera, Uncinia rubra, Stipa tenuissima, Briza maxima.
  • Conifers– Thuja occidentalis ‘Smaragd’ (slow growing).
  • Shrubs – Ilex aquifolium, Buxus sempervirens (slow growing), Choisya ternata, Cotoneaster horizontalis, Pyracantha ‘Orange Glow, Vinca minor ‘Variegata’, Nandina domestica ‘Fire Power’.
  • Perennials – Acanthus spinosus, Epimedium grandiflorum, Artemisia schmidtiana ‘Nana’, Ophiopogon planiscapus ‘Nigrescens’.
  • Bulbs – Narcissus ‘Tete a Tete’, Galanthus nivalis.

Grass/Steppe/Prairie

Prairies are temperate grasslands usually found in the Americas. Steppes are found in China and Russia. Grassland maybe arid or temperate climate.

  • Prairie planting mimics the effect of prairies in the wild by using large groups of grass and perennials to create a dramatic effect.
  • Piet Oudolf uses prairie planting, some of his gardens – Pensthorpe, Bonn and West Cork.
  • Is a late season style – using late flowering perennials mixed with grasses, plants that die well
  • 3 types – dry, mesic (somewhat moist) and wet. Mesic and dry prairie plants need loose soil with good drainage. Wet species grow best in badly drained areas. Match plants to soil type.
  • Plant in curves, instead of rows, it will give you a more natural look.
  • Allow one species to dominate, then blend into another.
  • Prairies can be good for wildlife.

Article about prairies – with plants and tips.

Plants

Grasses

  • Calamagrostis x acutifolia ‘Karl Foerster’
  • Miscanthus sinensis
  • Miscanthus ‘Morning Light’
  • Miscanthus sinensis ‘Zebrinus’
  • Miscanthus ‘Ghana’
  • Pennisetum Orientale
  • Stipa gigantea
  • Stipa tenuissima

Perennials

  • Rudbeckia fulgida
  • Helenium ‘Moerheim Beauty’
  • Echinacea Sussex Prairie Seedling
  • Veronicastrum virginicum
  • Eryngium bourgatii
  • Asters novi-belgii
  • Veronicastrum virginicum ‘Diana’
  • Anemone x hybrida
  • Verbena bonariensis
  • Persicaria ‘Firedance’

Potager

‘Jardin potager’ was the French term for an ornamental kitchen garden, a decorative way of growing vegetables and herbs. Potagers took the neat rows of kitchen vegetables to a new level by planting in patterns, usually in a formal framework evergreen rather like a knot garden or parterre. Edible flowers and herbs, and non-edible companion plants or purely decorative flowers are planted with the vegetables. Plants are selected for usefulness as well as for colour and form.

While the aim is to have a very decorative and productive part of the garden, it is hard to combine these two objectives fully. For decorative ranks of plants like at Villandry, grow plants that hold their shape for a long time ( like cabbages and leeks), this is more decorative than functional. To have a really productive vegetable garden there needs to be a succession of a small number of each vegetable, so that not all lettuces are ready at once and so they can be harvested as needed. Decorative fruit and vegetable gardens, involving trained fruit, flowers and vegetables in a setting of formal beds – raised, edged with woven willow or hazel – are the most practical way to get the potager effect and still be able to use vegetables.

Plants

  • Globe artichoke (Cynara scolymus)
  • Ruby chard (Beta vulgaris)
  • Lavandula orientalis ‘Hidcote’
  • Verbena bonariensis
  • Runner bean (Phaseolus coccineus)
  • Allium atropurpureum
  • Helianthus annuus

Some articles on designing a potager and what plants to use:

2.2 Describe the annual maintenance of the areas listed in 2.1.

Woodland

Mostly a low maintenance style of gardening.

  • Pruning – trees may require some pruning in their first years and following that dead limbs may be pruned out. On the whole woodland garden trees are left alone, but crown thinning can be used to let more light in.
  • Raking – leaves should be left to break down to a mulch that will provide protection from frost and nutrients. However an exception to this is when leaves show signs of fungal disease or if leaves fall particularly thickly so that ground cover plants are swamped.
  • Weeding – remove any invasive species and control planted ground cover plants that may be too vigorous.
  • Watering – mostly not necessary, but if there is a drought on then every two weeks may be useful.

Wildlife

  • January – plant trees and shrubs now, ball on pond, clean and put out new bird boxes.
  • February – Provide bird food on tables and in feeders.
  • March – Good time to build a pond, keep feeding birds.
  • April – Plant pond plants after last frost, sow wild flower plugs and seedlings in meadow, cut meadow to 10cm.
  • May – prune trees and shrubs.
  • June – keep a check on pondweed and algae
  • August – water plants and shrubs during establishment (3 years), keep pond topped up with rain water
  • September – sow seeds for wildflower meadow, cut meadow after it has finished flowering
  • October – Clear out ponds before frog hibernation, start feeding birds
  • November – tree planting, cut diseased and damaged trees, clean out bat boxes

Sensory

Will depend on the specific plants used.

  • Thymus, Nepeta – herbs generally – need to be cut back in autumn.
  • Grasses should be left over winter and trimmed or thinned in spring depending on species.
  • Bamboos may need containment to prevent them running.
  • General border maintenance of shrubs, herbaceous plants and climbers will be necessary, but extra care will be needed to avoid encroachment by overhanging branches and to keep paving surfaces clean, leaf-free in autumn and in a safe condition, and to make sure woodwork is sound and splinter-free.

Low maintenance

Amenity low maintenance gardening usually gets visited two or three times a year and shrubs are cloud pruned, Buxus is trimmed, ground weeded. Attention isn’t paid to flowering times.

Grass/Steppe/Prairie

Takes a lot of work to establish, but after that is easy.

When you are growing from seed, controlling weeds during the first two or three years is tricky.

Prairie perennials spend the first few years developing a complex root system while remaining small seedlings above ground, making it difficult for them to compete with common weeds that put all their energy into producing above ground growth. Using plants that have already grown to a reasonable size can help this, otherwise frequent weeding is important.

Irrespective of whether you intend to use seeds or plants, the area to be planted must be completely free of weeds and grasses. Heavy clay soils should be dug to a depth of 30 cm to break up compaction. Organic matter such as compost, leafmould and sharp sand can be worked into poorer clay soils to improve aeration and water infiltration. Very dry sandy soils in particular will be improved by the addition of organic matter to increase their nutrient and water holding properties.

In the wild prairies are controlled by burning. Cultivation mimics this by mowing and removing clippings. Mowing and raking every spring also helps control weeds and promote growth. Mow in late June with the mower blade set about 20cm, this will cut back early growing annual weeds, but not affect slower-growing prairie grass and plants.

After 4 or 5 years, mow once a year after the seeds have fallen, or preferably, in the early spring. Remove clippings to expose crowns for regrowth.

Potager

Maintenance is the same as it would be for a vegetable patch, so digging (or no dig system), planting, feeding, managing pests, disease and weeds, and harvesting. Fruit trees and shrubs will require pruning and training. Using companion planting can reduce work (reducing pests and keeping down weeds) and can also make the potager more attractive. In general it will rely on its design lines ( trained fruit, bed shapes, arches and frameworks) and hard landscaping for winter interest.

3. Understand specialist pruning for effect.

3.1 Describe the use of pruning to produce decorative forms of ornamental trees and shrubs, including pollarding, pleaching, topiary, cloud pruning and wall-training.

Pollarding

Coppicing is cutting a plant almost to ground level each year to promote new shoots, whereas pollarding is cutting back for the same reasons, but keeping a length of stem, so that the plant (often a tree) is much taller. Originally this was done to keep new growth above the height of animals grazing in the field. Pollarding now is used to keep limes and planes within bounds and away from power cables, it is also used to give winter colour from Cornus and Salix at height.

Plants used on:

  • Fraxinus spp.
  • Tilia x europaea
  • Ulmus spp.
  • Sambucus spp.
  • Eucalyptus spp.
  • Platanus x hispanica
  • Morus spp.
  • Quercus spp.
  • Acer negundo
  • Liriondendron

Once young trees have reached the desired height, they can be pollarded, on a shrub this may be only 1m, on a tree the trunk should support three or five branches, twiggy growth appearing at the ends of these branches. Initially new branches are held weakly in place, but over the years a strengthened pollard head forms.

Pollard late winter or early spring, not in autumn as decay fungi may enter the cuts.

Pleaching

The art of manipulating trees into a raised hedge.

  1. Deciduous tree are planted in lines.
  2. Branches are then woven together and due to Inosculation (see below) the trees grow together to form a solid barrier
  3. Once merged together the trees can be clipped to their shape.

Inosculation is a natural phenomenon in which trunks, branches or roots of two trees grow together. It is biologically very similar to grafting. It is most common for branches of two trees of the same species to grow together, though inosculation may be noted across related species. It can also be used to create interesting forms.

Topiary

  1. Grow the plant to roughly the correct size
  2. Roughly prune to shape, may require removing number of the branches
  3. Once the plant has bulked up, more closely prune it
  4. Topiary can also be created using ivy and a wire frame.

Cloud pruning (Niwaki)

Cloud pruning is a Japanese method of training trees and shrubs into shapes resembling clouds. It is known as ‘Niwaki’, the translation of which is ‘garden tree’. The style is said to depict the distilled essence of the tree. This type of pruning does not have to be used in solely Japanese-style gardens; it can be used as a feature in gardens of many different styles, formal gardens often use it.

  • Box (Buxus sempervirens)
  • Yew (Taxus baccata)
  • Pine (Pinus)
  • Japanese privet (Ligustrum japonicum)
  1. Select tree/shrub with interesting branch formation
  2. Remove unwanted branches and twigs so that the main branches are bare.
  3. If the plant is to grow taller and wider don’t prune tips at end of branches, but the side shoots around the ends of branches can be shaped into clouds
  4. Once the plant has reached the desired length and height trim the tips to encourage branches so that the clouds fill out.
  5. Manipulate the branches using stakes or weights to get the correct shape.
  6. When to prune – annually in late summer (but if flowering, then after flowering).

Wall training

Soil at the foot of any wall is invariably poor and dry, dig out  to a depth of 45cm, then replace it with good-quality topsoil mixed 50:50 with well-rotted organic matter, to make a bed 60cm wide.

Use bamboo canes for climbers – a fan of canes leaning from the base of the plant to the wall. RHS article on training climbers.

Semi-tender wall shrubs – train slightly delicate shrubs flat over the wall, tying them to netting, trellis or horizontal wires supported by nails. Plants to use include Cytisus battandieri, Phygelius capensis and Carpenteria californica.

Woody climbers – Trachelospermum jasminoides, Jasminum officinale.

Although pruning depends on the individual needs of the plant, some tasks are very similar:

  •  Tie in new growth regularly to fill the allotted space.
  •  Tie in side shoots to fill gaps.
  •  Prune back overlong shoots.
  •  Removed dead, diseased and damaged shoots.
  • Remove crossing (touching and rubbing) and congested shoots.
  • Pruning takes place after flowering on those that flower on the previous year’s growth, or in late winter or early spring for those flowering on the current year’s growth.
  • After pruning, mulch and feed.

Pruning specific to climber types

Vigorous climbers –  No regular pruning is needed, prune only to keep to alloted space. Eg Parthenocissus, Trachelospermum.

Moderately vigorous climbers – shorten side shoots to within three to four buds of permanent framework. Examples:  Solanum crispum, Sollya heterophylla.

Wall trained shrubs – shorten sideshoots to within two to four buds of the permanent framework of branches. Remove shoots growing towards the wall. Examples: Chaenomeles, Garrya elliptica, Fuchsia.

Regenerative pruning – always carried out in autumn or winter. Take out a third of old stems at a time. Article.

Problems

Pruning at the wrong time of year may result in a poor display the following flowering season. Plants should recover and flower again fine in their second flowering season after pruning, so no long-term damage will have been done. Renovated plants that have been hard-pruned may take longer to re-start flowering.

3.2 Describe the use of pruning to produce specialist decorative forms suitable for fruit growing, including fan, espalier, cordon, stepover and festoon.

Fan

Fan trained trees consist of a short clear stem of about 0.5m and a set of branches above this arranged to form a fan shape.

RHS article – the following is essentially and abridged version of the article.

Plants: apple, pear, cherry and fig

  1. Choose semi-dwarfing or semi-vigorous rootstocks. eg     Apple: ‘M26’
  2. Choose a wall or fence of sufficient height – 2m.
  3. Erect strong horizontal wires starting 40cm above the ground, 4-10cm away from the wall and 15cm apart. Use 1.2mm galvanised wire.
  4. Choose either a maiden whip (a one-year-old tree with no branches), a feathered maiden (with two branches suitably positioned to be the main arms of the fan) or a part-trained fan
  5. Plant trees 15-22.5cm away from the wall or fence, sloping slightly towards it.
  6. In spring, cut back the main stem to about 40cm, leaving three strong buds
  7. In summer, erect two canes at 45 degree angles and tie in two of the branches that should develop from the buds to form the ‘arms’ (one either side). Remove any other shoots if they develop from the trunk
  8. In the second spring, reduce the ‘arms’ by two-thirds to an upward-facing bud. Remove any other growth from the trunk
  9. In summer, choose four shoots from each ‘arm’: one at the tip to extend the existing ‘arm’, two spaced equally on the upper side and one on the lower side. Tie them in at about 30 degrees to the main ‘arm’ so they are evenly spaced apart (using canes attached to the wires if necessary).
  10. Rub out any shoots growing towards the wall and pinch back any others to one leaf.
  11. In the following spring, cut back each of the four branches on each side by one third, cutting to an upward-facing bud if possible.
  12. During the growing season, tie re-growth from the tips of these branches into the framework to extend the main branches
  13. Any side-shoots that develop where there is space within the framework can be tied in.

Espalier

RHS Espalier

Espalier tree consist of a vertical stem and a set of horizontal arms or tiers extending either way bearing short lateral branches or spurs on which the fruit is produced.

Timing – summer

Plants: apple or pear, also Cotoneaster or Pyracantha. Rootstock can be MM106

Wires erected as above, plants 3.75-6m apart according to vigour

  1. When planting an unfeathered maiden, cut back the main stem to 30cm from the ground
  2. Allow the top three buds to grow out in spring, train the top one vertically up a cane, the others two to canes at 45 degrees to the main stem. In November, lower the two at 45 degrees so they are horizontal, tie them in.
  3. Cut back the vertical stem to within 45cm, leaving two buds to form the next horizontal layer and the top bud to form the new leader.
  4. The following year train the second tier in the same way as the first. Cut back competing growths on the main stem and sideshoots from the horizontal arms back to three leaves above the basal cluster.
  5. Repeat the process until desired size.
  6. Remove the blossom in spring, for the first three years, so all of the energy goes into plant growth.

Cordon

RHS Cordon

Single stemmed trained forms of fruit trees or bushes, consist of one main stem with short side shoots that bear fruit. They can be grown parallel, in diagonal lines or pleached together.

Suitable for apples and pears, spur bearing, non vigorous types.

Timing – Plant in winter, prune in summer

  1. 3 horizontal wires erected, 30cm from ground, 60-90cm apart.
  2. Plant in winter in an open but sheltered position. Use one-, two- or three-year-old cordons.  Use M27 rootstock (extremely dwarfing) or M9 rootstock (very dwarfing) for apples.
  3. Plant trees at an angle of 45 degrees, 60-90cm apart. (The wider spacing within the row is for infertile, shallow or sandy soils). Tie the cordon to the diagonal bamboo cane fixed to the wire support with a soft string.
  4. After planting, cut back all laterals (side shoots) longer than 10cm to three buds, leaving the leader and any short laterals unpruned.
  5. Summer pruning is carried out in August, when sideshoots over 22cm long are cut back to three leaves. Stems  from existing sideshoots or spurspruned to just one leaf beyond the basal cluster.
  6. Leave shoots less than 15-22cm long until mid-September and then shorten to one leaf beyond the cluster of leaves at the base.
  7. Prune any growth that forms after summer pruning in September. Prune to one leaf beyond the last cut.
  8. Tie the leading shoot (‘leader’) in to the support until it reaches the required length. Thereafter, prune it back and treat subsequent growth as for other laterals.
  9. When the cordons reach the top wire they may be lowered from 45 degrees to 35 degrees in early spring.  Again, once the cordon has reached the top of the support, prune it back in late summer.
  10. Over time the spur system can become over-long or complicated. Remove older and unproductive sections of the spurs. Occasionally rejuvenate the spur system by pruning back to a stub 3-5cm of the main stem cutting above a well-placed dormant bud.

Stepover (aka horizontal cordon)

Stepover

These have a short stem and horizontal branches and are a modified training method of the cordon.

Timing – Prepare support and plant in winter; start training in spring.

Plants – spur fruiting apple trees on M27 rootstock.

  1. It is necessary to start training on very young trees. Choose a supple maiden whipThe main stem must not have been pruned to encourage branching.
  2. A single wire is stretched between supports 1.5-2m apart, 45cm above ground.
  3. In winter, plant the maiden whip next to the post and tie in.
  4. In spring, start gradually and carefully bending the tree towards the horizontal wire. Tie the stem to the wire at several places to distribute the pressure and ensure it bends evenly, the gradual bending of the stem may take the whole growing season.
  5. In summer, shorten any laterals (side branches) that develop from the main stem to three leaves.
  6. Do not prune the leader until it reaches the desired length, then prune just above a bud.
  7. The subsequent summer and winter pruning is the same as for a single, oblique cordon.
  8. If the growth becomes more bushy and vigorous at the bent trunk end of the tree, an additional winter thinning may be necessary around that part.

Festoon

Festoon

This is training rather than pruning and refers to tying down branches of fruit trees and roses so that they form a balloon shape causing them to flower and fruit more. This is now more common in roses where willow hoops are used to bend stems so that they produce more flowers.

4. Know a range of options available for urban gardening.

4.1 Describe a range of options available in an urban situation, to include small front gardens; courtyards; container gardens; roof gardens; living walls; street plantings; conservatories and community gardens.

4.2 Identify any specific establishment and maintenance issues associated with the options in 4.1

Small Front Gardens

  • They need to be functional – a place to store bins, cars and bicycles, but also attractive since they are on show.
  • There needs to be good access for milkmen and postmen, with an obvious and quick route to the front door.
  • Hedges should be no more than 1m high so that intruders can be seen breaking in from the road.
  • Use SUDS when installing a drive, using reinforced grass or permeable macadam (Tarmac).
  • There may be a problem with rubbish blowing in from the road.

Establishment and maintenance issues

  • People don’t usually enjoy gardening in the front, due to pollution and lack of privacy, so ideally there should be plants that don’t require too much maintenance – shrubby plants, grasses and gravel gardens are good and reduce problems of watering.
  • Compaction may be a problem following building work – deep dig and add grit.
  • Front gardens on busy roads may be affected by salt spray – salt tolerant plants are Escallonia and Eleagnus, also pollution can be a problem.
  • Littering may be a problem, as is blown in litter. No gate may equal dog poo.
  • Front gardens may be subject to covenants restricting walls, hedges and planting.
  • Care must be taken not to overshadow the house or block light, eg Araucaria araucana is bad.

Some good front garden trees:

  • Betula albosinensis –cinnamon peeling bark
  • Genista aitnensis – July flowers
  • Gleditsia triacanthos

Courtyards

Description

Enclosed, introspective gardens that often use Moorish elements of water, foliage and scented plants. They use a barrier and sounds of water block out noise, scents block the smell of cooking. The enclosed nature of it can also create a microclimate where half hardy plants can grow.

Establishment and Maintenance issues

  • Access to courtyards for construction may be limited
  • Planting is often in raised beds or containers=more feeding and watering
  • Possibility of too much shade
  • Enclosed areas may lead to mildew and mould on hard landscaping.

Container Gardens

Description

Pots can be of many sizes and materials, such as clay, metal or plastic. Or more innovative containers might be old boots, sinks or baskets. Containers can be moved to suit both appearance and climate (eg moving plants to when the sun reaches most at that time of year, moving out of frost pockets.)

Establishment and Maintenance issues

Mainly watering use drip irrigation and drought tolerant plants (Yucca, Phormiums, Aeoniums). Plants will need regular feeding and the compost needs to be replaced annually.

RHS article on container maintenance

Roof gardens

Description

Can be intensive, semi extensive or extensive. Intensive are over looked roof gardens, planted in 15cm of soil, requiring a lot of water and maintenance. Extensive are not seen, planted on a minimum of 2cm substrate with more drought tolerant plants, appearance is not so important so plants are allowed to turn brown. Semi extensive have a slightly greater depth of substrate to allow more natural planting.

Establishment and Maintenance issues

 RHS Article on Roof Gardens

Living walls

Description

RHS Article on Living Walls

Establishment and Maintenance issues

Require more maintenance than living roofs, but provide sound/warmth insulation. Can have roots in air or in Leca. Stop roots growing into brickwork by providing plenty of water.

Street plantings

Description

Advantages:

  • reduce urban heat island effect by shading and evapotranspiration
  • Reduce pollution by intercepting particulates and absorbing greenhouse gases
  • Reduce flooding by intercepting rainfall
  • Reduce stress

Establishment and Maintenance issues

When choosing trees there needs to be an awareness of drought tolerance, excess shade cast and effect on biodiversity (native species?)

A system of pruning needs to be in place to stop street trees encroaching on property or hitting power lines.

Conservatories

Description

A heated, glass area to sit that is attached to the house, but filled with tender plants. Usually heated.

Establishment and Maintenance issues – good air circulation and heating appropriate to the plants is important. Maintenance problems are often structural such as too hot in summer, too cold in winter, leaking and so on. If building it will need planning permission.

Community gardens

Description

Can be small vegetable plots, large parks or greenhouses. Often built around a theme or aimed towards specific people to care for it (ie children or adults with learning difficulties.)

Establishment and Maintenance issues – finding and keeping reliable knowledgeable people to work on the gardens. Can be an organisational nightmare, may have a situation where everyone wants to manage or no one does – or everyone wants to have control, but no one wants to take official responsibility.

5.Understand how water sustainability can be built into a garden.

5.1 Describe how modern gardens can be adapted to conserve water and reduce run-off, including green roofs; water collection, storage and recycling; permeable surfaces; and mulches.

Green Roofs

Green roofs can help by intercepting rain as it falls onto rooftops, letting it soak into a substrate – with some excess draining down but much of the water being held and then taken in by roots and transpired by leaves. Extensive green roofs can be ‘retro-fitted’ to many flat or sloping roofs in cities because of the relatively light weights involved.

Plants for this type of roof have to survive extremes of temperature and relative periods of drought – Sedums are not exciting, and there are many other plants being trialled, but they do seem to work well.

Flat roofs are the best for greening and a flat, asphalt-covered garage is ideal for a carpet of sedums. By adding a concrete support filled with growing media you could choose to grow a wildflower meadow.

Tiled or corrugated garage roofs are not suited to living roofs but will support moss and lichen which are useful wildlife habitat. You can develop a green roof on your shed but many need additional reinforcement first.

  • Intensive green roofs – old-style roof gardens which are planted either in containers or at least a 15 cm depth of soil or substrate, and designed to be used or at least overlooked by people. Have high demand of water and maintenance.
  • Extensive green roofs – not generally intended to be used by people, or even to be seen in many cases. They are massed low plants on a substrate of 2-15cm depth, and therefore much more lightweight; the vegetation often goes brown in high temperatures, so these are also called ‘ecoroofs’ as they aren’t always green.
  • Semi-extensive green roofs – use the same lightweight growing media, but with a slightly greater depth to allow a greater and often more naturalistic range of plants to grow, such as the sustainable perennial mixes being researched by the University of Sheffield and

Construction – build a frame, line with butyl liner, filled with potting compost with lots of perlite.

Advantages to green roofing

  • Reduced energy and maintenance costs
  • Long roof life: Protects against UV and weather damage
  • Provides a habitat for fauna and flora species
  • 70-90% of rain water retained, easing pressure on drains and prevents river pollution
  • No reflected heat and prevents sealed surface heat build-up
  • Cools buildings in summer and insulates in winter
  • A useful, recreational space for roof gardens or terraces

Water collection

  • Grey water – all household waste water is called grey water, can be specially piped from the house into a bed or collection unit, but can’t be too polluted or may need treating/filtering.
  • Water butt – collects rain water from roof.

Rain garden

Is a dip or hole in the ground, planted up, where water run off from roofs and drain can collect. Because they prevent water running straight into storm drains, they reduce water pollution. The plants in the rain garden should be native plants with deep roots that can cope with both excess water and drought conditions.

Rain Garden Wikipedia

Mulches

  • Bark chipping (bio degradable, improves structure, can remove nitrogen from soil)
  • Strulch (cheap, bio degradable)
  • Gravel (can spread, looks attractive)
  • Landscape fabric (needs to be covered with gravel or bark or looks odd)
  • Black plastic (block water entering soil, cheap)

Benefits:

  • retains moisture in summer
  • suppress weeds
  • improve soil texture
  • deter some pests
  • protect plant roots from extreme temperatures
  • encourage beneficial soil organisms
  • decorative

Can be biodegradable (release nutrients and improve structure) or non-biodegradable (Eg landscape fabric).

How to apply: 5cm-7.5cm, lay over moist, weedless soil, keep away from stems.

SUDS

  • Permeable paving.
  • Infiltration and attenuation systems.
  • Filter drains.
  • Swales.
  • Ponds and wetlands and releas it slowly to the environment.

Porous paving – can be:

  • Infiltration system = porous pavement +geotextile + granular sub base + geotextile (which filters).
  • Attenuation system = similar to above, but with outfall pipe on impermeable layer so that water is contained.