How to Build Your Garden in Contours
Not everyone is blessed with an easy, level site for a garden, and those who are often long for a more varied terrain. Whatever your preference, there is no doubt that level ground makes gardening easier and that changes of level create a set of problems, both in planting and with access. But however steep the site, so long as you work within its limitations, it is perfectly possible to have an interesting and fulfilling garden. Virtue must be made of necessity.
Steeply sloping gardens lend themselves to different treatments depending upon their aspect. South-facing slopes receive the maximum heat from the sun and are especially suitable for Mediterranean plants or make good scree gardens. Drainage will be fast, which is an advantage to many slightly tender plants. These slopes also offer the possibility of creating streams or waterfalls, which can be made to be as formal or informal as required. Terraces can be constructed across the slope, as in the great villa gardens of Italy, to maximize the potential for planting, using either retaining walls or turf banks.
Cold north-facing slopes make good woodland gardens, but will equally make an ideal site for a terraced alpine garden because they are naturally well drained, fully exposed to light, but without the drying heat found on a south-facing slope.
The approach used on a sloping site also depends on its relationship to the house. A garden that slopes up from the house will be far more dominant than one that slopes away: it will fill the whole view and offer the opportunity for a real tour de force, whether formal or informal. It could be perfectly symmetrical with pairs of circular steps or an idealized Japanese mountain waterfall. Sites which slope away from the house are less imposing in themselves and throw the eye outwards into the view beyond. It might be Mount Fuji, a power station or just your neighbour’s garden. Whether this view should be incorporated into the garden’s design or excluded to produce an enclosed oasis will depend on its merits or demerits. If the view is good, and it can be relied upon to remain so, then make the most of it. If the focus needs to be kept within the garden then try using a formal arrangement of large pots or upright conifers. These may not mask a poor view but they will give details of some substance to attract the eye.
Irregular changes of level within a garden can make it more interesting and offer the chance to create surprise views and features. The move from one level to another does not necessarily have to be negotiated in one go; a flight of steps can be split up and intermediate levels inserted in between. Steps are one of the most significant built features of a garden and deserve to have plenty of attention given to their detail. If the garden contains large mounds or hollows, consider enlarging them to create a major feature, such as a pond or a mount or rockery.
During the planning stage always keep in mind the maintenance implications of the finished garden. Steps are attractive, but they can stop easy access with a wheelbarrow or lawn mower. Terraces are fine, but will there be suitable access to take away prunings? Should the compost heap be positioned at the bottom or the top of the slope? Where access is limited, it is often better to opt for a style of planting that requires little pruning, such as an alpine or heather garden.
Finally, soil erosion can be a problem on banks and can be solved in a variety of ways. Turf banks will hold the soil once they are established, but ruts can soon develop where people constantly walk. Ground cover plants such as Hypericum calycinum, which have underground stems to bind the surface soil in a tight mat, can be used to stabilize a bank, but they may take some years to become effective. In extreme cases, terracing and channelled drainage may be essential.
