Deciding what is possible
Tackling the site
Ways of coping
Considerations
Plant suggestions

The prospect of gardening on a steeply sloping site is often looked on with fear and trembling but, with imaginative use, changes in level can greatly enhance the beauty and interest of a garden. Many older or disabled people are daunted by the prospect of coping with what seems like a mountainside outside their back door. Here we consider what is necessary to enhance and improve a sloping site.

Deciding what is possible

Before any other considerations, it is important to decide what is really wanted from the garden. For instance, do you simply want low maintenance cover for their awkward slope or to use the garden in a more intensive way?

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Often, a sloping garden doesn't lend itself easily to conversion for a disabled user, having steep steps, inaccessible rockeries and ridiculously sloping areas of lawn. But it may be found that the garden falls into distinct areas which can be incorporated into a suitable design.

Fig. 1 The dotted line indicates the original variable slope of the garden

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An extreme slope in a small garden can only be tackled by removing much of the soil - a very arduous and expensive business. It must be ascertained whether lowering of gradients is appropriate or possible in relation to the length of garden and that the earth moving does not interfere with service pipes: sewage, gas, electricity, etc. In this situation, the site should be professionally surveyed to determine what is possible or practical.

Another point to bear in mind is that if access to the garden is solely through the house itself, life will be extremely difficult for the duration of the work.

Finance

It is worth checking with local social services departments to see if any voluntary or state schemes operate locally which undertake manual labour without charge. In some areas work of this kind can be allocated to people serving community service orders (under supervision). Thrive is in touch with some projects that provide gardening services. Contact them to see if there is a group in your area. You might also like to get in touch with your local Volunteer Bureau or CVS and ask if there are any schemes, including Care and Repair schemes, in your area. Whatever help is available, material costs do have to be met and these may be vast where an ambitious project of retaining walls and paths is planned. The Gardening for Disabled Trust can offer financial help for older and disabled gardeners. Contact them at: The Freight, Cranbrook, Kent TN17 3BR.

Aspect

An exposed north-facing slope will offer little warmth and sunlight, so elaborate changes may not be worthwhile. Look into tolerant low-maintenance groundcover for this site (see planting suggestions) and maximise on garden areas that have a better aspect!

Soil and drainage

When soil levels are to be altered, it is important to consider where the rich topsoil is going and where the impoverished sub-soil will be revealed.

Parts of the garden that do not require direct access can be left steeper than others, although with certain soils, if the angle is too steep, land-slip may occur. Heavy clay on a bank is particularly difficult to dig and drain. Banks can be held together by appropriate planting or supported by retaining walls.

All raised or sloping areas drain faster than level ground and can subsequently become very dry. Incorporating organic material into the topsoil in these situations can help to improve its water-holding properties. The type of topsoil and subsoil will also dictate the need for artificial drainage on slopes or terraces. For instance, light sandy topsoil on top of clay subsoil may result in boggy conditions where the two soils meet. In this case, drainage pipes or outlets in the retaining walls will be necessary.

Subsidence

Soil that has been moved takes time to settle and some sinking will occur over a period of weeks or even months. It is unwise, therefore, to plant up newly created areas permanently until the soil has been allowed to settle. In such cases, it is better to plant annuals for the first year. Path sites can be sown with quick growing rye grass until the soil has settled, prior to laying new surfaces.

Paths, gradients and ramps

A low-gradient path may be central to the design so that all other features are required to fit round it. A 1 in 15 gradient means that for every 15 feet travelled, the rise is not more than one foot and to achieve this, it may be necessary to alter the course of an existing steep path. Choice of path material is important where mobility is a problem. Refer to the Access section for further details.

A sloping path may become a river in wet weather, so consideration should be given to adequate drainage. A guttering system along the edge of the path is one option. Another very basic solution is an area of deep gravel to act as a soakaway. Expert opinion on an appropriate system may be necessary to ensure the comfort and safety of path users.

Steps

Wide, shallow steps may be appropriate in some parts of the garden and handrails may be necessary (the appearance of these can be softened by growing climbers along them). For those who are unsteady or have to use a standard walking frame, a set of five steps with 75cm (18") treads and 10cm (4") risers should be quite manageable. Timber or railway sleeper steps look appealing, but beware, they can be treacherous in wet weather. Steps can be sunk into an existing slope or built as an alternative to a sloping path.

Planted banks

The possibilities are endless provided the subjects chosen will enjoy drought-like conditions. The aspect of the bank is also important and will determine plant choice as regards sun or shade requirements. If the soil is sandy, planting to contain the slope may be necessary. Dense ground cover is desirable where access for weeding is limited. This type of planting can be greatly enhanced by underplanting with bulbs of all kinds that then grow up through the low-growing shrubs. Miniature winter flowering bulbs such as Chionodoxa look good under deciduous shrubs. Any exposed subsoil will need enriching and cultivating before being planted. The incorporation of organic matter will also improve soil structure, which is equally important on a slope where leaching of nutrients and excessive soil erosion could take place.

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Helianthemum, the well-known rock rose, offers greyish foliage and a vast range of flower colours; it covers rapidly and its relatively short flowering period is spectacular. Needs full sun and is useful for dry banks.
Cytisus x kewensis - broomlike flowers, bright yellow.
Cerastium 'Snow in Summer' - beware, this becomes hard to contain; it spreads.

Evergreen and variegated shrubs

There is a range of conifers available that are suitable for banks. Particularly useful are those with a prostrate or low-growing habit, for example:
Juniperus x media 'Pfitzerana Aurea'
Juniperus virginiana 'Grey Owl'
Juniperus squamata 'Blue Star'
Chamaecyparis lawsoniana 'Pygmea'

Euonymous fortunei 'Emerald Gaiety' and many other cultivars these are tough plants, not particularly rampant and good in shade.
Vinca species - blue periwinkle; the minor and variegated varieties are not as vigorous as the "major" varieties.
Hedera Many varieties of ivy can be grown very successfully as ground cover, e.g. Hedera helix 'Buttercup' and Hedera hibernica.
Hypericum calycinum: 'Rose of Sharon', a classic bank-coverer, can take over but tolerates shade and has the bonus of large yellow flowers.

Climbers grown as ground cover

Clematis montana Vigorous, small pink or white early flowers; C. tanqutica Many small lantern-shaped yellow flowers followed by fluffy, silvery seed heads will scramble through shrubs, over dead stumps and ugly walls.

Ground cover shrubs

Ground cover roses are useful for sunny banks; Rosa rugosa 'Max Graf' is one possibility. Basic low maintenance sun-loving shrubs (should be planted in clumps of three or five, with centres about one metre apart) include:
Potentilla fruticosa - a tough shrub with saucer-shaped yellow flowers.
Spiraea species pretty adaptable plants, these, and many also tolerate shade.
Berberis the dwarf species make excellent ground cover and are also famous for cat-deterring properties.
Cotoneaster - especially horizontalis - flowers followed by berries and a dense, interesting herringbone habit.
Lavender - especially 'Munstead' variety, makes a wonderfully fragrant border to shallow steps.

Ground cover for dry shade

Epimedium perralderianum - dense cover of leaves with interesting autumn colour.
Astrantia major, delicate surreal flowers and attractive palmate leaves.
Ajuga reptans creeping blue bugle.
Berberis species: very prickly, many varieties, some with flowers and berries and some very large!

All types of Viola, especially a variety called 'Johnny Jump-up';
Aubrieta, Arabis (evergreen) and other standard rockery plants.
Campanula - the spreading kind.
Saxifraga delicate spreading rosettes.

Evergreen shrubs for raised planting areas and containers.

All types of Hebe (Veronica); Some are variegated and many others are late flowering and attract bees;
Rosemary - especially low growing varieties
Stachys lanata - furry grey leaves.
Santolina - cotton lavender, with delicate silver foliage, aromatic and has yellow daisy-like flowers.

Conclusion

This section has discussed options available in coping with sloping gardens. It should be emphasised that the design stage is all-important; if there are any doubts, professional advice should be sought before even a spade is lifted.

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