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
|Allium, Crocosmia ‘Lucifer’, Crocus, Hyacinthus orientalis ‘Blue Basket’, Narcissus poeticus, Tigridia
|Lilium, Osteospermum jucundum, Celosia ‘Fresh Look Mix’, Lobelia erinus, Tagetes patula, Viola × wittrockiana, Lobularia maritima, Zinnia elegans ‘Dreamland Series’, Tulipa ‘Little Beauty’
|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
|Gaillardia ‘Arizona Sun’, Coreopsis grandiflora, Cosmos atrosanguineus, Dahlia ‘Garden Party’, Pelargonium x hortorum, Impatiens Accent Series, Capsicum annuum, Verbena ‘Lawrence Johnston’
|Alstroemeria , Canna, Musa basjoo
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 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.
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 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.
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.
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.
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.
- 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 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).
- 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.
- 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.
- 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
- 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.
- Mentha spicata – mint.
- Rosmarinus officinalis – rosemary.
- Tropaeolum majus – leaves can be used in salad.
- Allium schoenoprasum – leaves can be used in salad.
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.
- 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.
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.
- Calamagrostis x acutifolia ‘Karl Foerster’
- Miscanthus sinensis
- Miscanthus ‘Morning Light’
- Miscanthus sinensis ‘Zebrinus’
- Miscanthus ‘Ghana’
- Pennisetum Orientale
- Stipa gigantea
- Stipa tenuissima
- 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’
‘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.
- 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.
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.
- 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
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.
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.
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.
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.
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
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.
The art of manipulating trees into a raised hedge.
- Deciduous tree are planted in lines.
- Branches are then woven together and due to Inosculation (see below) the trees grow together to form a solid barrier
- 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.
- Grow the plant to roughly the correct size
- Roughly prune to shape, may require removing number of the branches
- Once the plant has bulked up, more closely prune it
- 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)
- Select tree/shrub with interesting branch formation
- Remove unwanted branches and twigs so that the main branches are bare.
- 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
- Once the plant has reached the desired length and height trim the tips to encourage branches so that the clouds fill out.
- Manipulate the branches using stakes or weights to get the correct shape.
- When to prune – annually in late summer (but if flowering, then after flowering).
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.
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 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
- Choose semi-dwarfing or semi-vigorous rootstocks. eg Apple: ‘M26’
- Choose a wall or fence of sufficient height – 2m.
- Erect strong horizontal wires starting 40cm above the ground, 4-10cm away from the wall and 15cm apart. Use 1.2mm galvanised wire.
- 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
- Plant trees 15-22.5cm away from the wall or fence, sloping slightly towards it.
- In spring, cut back the main stem to about 40cm, leaving three strong buds
- 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
- In the second spring, reduce the ‘arms’ by two-thirds to an upward-facing bud. Remove any other growth from the trunk
- 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).
- Rub out any shoots growing towards the wall and pinch back any others to one leaf.
- 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.
- During the growing season, tie re-growth from the tips of these branches into the framework to extend the main branches
- Any side-shoots that develop where there is space within the framework can be tied in.
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
- When planting an unfeathered maiden, cut back the main stem to 30cm from the ground
- 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.
- 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.
- 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.
- Repeat the process until desired size.
- Remove the blossom in spring, for the first three years, so all of the energy goes into plant growth.
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
- 3 horizontal wires erected, 30cm from ground, 60-90cm apart.
- 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.
- 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.
- After planting, cut back all laterals (side shoots) longer than 10cm to three buds, leaving the leader and any short laterals unpruned.
- 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.
- Leave shoots less than 15-22cm long until mid-September and then shorten to one leaf beyond the cluster of leaves at the base.
- Prune any growth that forms after summer pruning in September. Prune to one leaf beyond the last cut.
- 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.
- 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.
- 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)
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.
- 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.
- A single wire is stretched between supports 1.5-2m apart, 45cm above ground.
- In winter, plant the maiden whip next to the post and tie in.
- 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.
- In summer, shorten any laterals (side branches) that develop from the main stem to three leaves.
- Do not prune the leader until it reaches the desired length, then prune just above a bud.
- The subsequent summer and winter pruning is the same as for a single, oblique cordon.
- 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.
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
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.
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
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
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.
- 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.
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.
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 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
- 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.
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
- 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)
- retains moisture in summer
- suppress weeds
- improve soil texture
- deter some pests
- protect plant roots from extreme temperatures
- encourage beneficial soil organisms
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.
- Permeable paving.
- Infiltration and attenuation systems.
- Filter drains.
- 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.