Dealing with Slopes and Changes in Level

Slopes can add a feeling of life to the garden, especially when they are incorporated into the overall scheme, becoming useful features in themselves, rather than simple accidents of geography. A completely flat piece of ground may well be a joy to cultivate – and mowing a level lawn is certainly easier – but it will always seem to lack a bit of the character of its undulating counterpart.

However, the overly-sloping plot has its problems too, particularly in terms of ease of working, drainage and convenience. Either way, it can often be necessary to consider how best to use slopes and changes in level to create your ideal garden design.

Steps and Slopes

Steps are the time-honoured solution to a slope which is too steep to walk up comfortably and can be used very constructively in the design, either to link the whole garden together, or alternatively to mark a transition between particular styles or themes within it. A wide variety of materials are available for making steps – the principle concern being that they are solidly constructed and safe – so building something appropriate to fit in with the rest of the surroundings should not be a problem.

Carefully crafted steps can also be the answer to creating more of a feeling of changing levels in flat, or nearly flat sites, to add a little extra interest to the garden. Constructing a few steps in the most modest of slopes will draw the eye upwards and make the plot seem more undulating – and for the pancake-flat garden, artificially creating low banks on either side of the steps – even if they are only quite low – can capture the same feel. With some imaginative planting to increase the apparent height even further, the overall result can be remarkably effective.

Terraces and Retaining Walls

If much of the plot lies at a steep angle, this can cause some real problems when it comes to cultivating it. One option to make life easier is to terrace the ground, using a cut-and-fill technique to level off the land in a series of shallow steps, leaving an expanse of workable flat ground with a small amount of sloping bank down to the next, and so on. Only very small scale terracing can be done by hand, anything more will require some serious earth-moving equipment – which needn’t be prohibitively expensive as diggers and their drivers can usually be hired for surprisingly low cost.

Where large drops in level are necessary, using a retaining wall is the most successful way of holding back soil on a slope. Tall retaining walls need to be of very strong construction to be able to withstand the weight of the soil behind, particularly when the ground is wet and it is important to have gaps for drainage – called “weep holes” – at the base, to allow the accumulated water to escape. If the wall needed is going to be higher than about 2ft 6 inches (75cm) tall, professional advice is essential to ensure that the final construction is safe and strong enough.

Planting Awkward Slopes

Unplanted banks in the garden can often suffer badly from wind and rain erosion, rapidly loosing soil and becoming unsightly. Grassing them over is one option, but keeping the grass cut, particularly in out-of-the way or inaccessible slopes, can be a problem, so often a more low maintenance approach is a better answer.

Planting ground cover shrubs, such as the low growing, horizontal varieties of Cotoneaster or Juniperus offers good protection from wind, tending to break up the gusts and reduce the air movement, helping stop soil being blown away too easily. Although they do take a season or two to become established, once they are, ground cover shrubs also reduce the effects of rainfall run-off.

Until they do grow large enough, a thick layer of mulch between the new plants will help soak up the water – and reduce weeds – although trying to keep it in place on a wind-swept bank may bring its own problems!

While gardening on a very steeply sloping site is certainly a challenge, some undulation and change of level adds interest to the plot and scope to the planting. Particularly in smaller plots, an overly-flat landscape can seem lacking in dimension and simply serve to reinforce the feeling of limited space; even a minor change in level offers an altered perspective – and provides the illusion of greater room. Getting to grips with the potential of slopes and levels is a very practical way to remind yourself what landscaping is really all about.