Introduction

There`s no getting away from it, New Zealand is a hilly country. Our stunning views and fabulous landscape often come with sloping, steep and even cliff-side gardens. These sites give rise to some fantastic design opportunities and practical challenges. Plants too can be appreciated anew from an elevated vantage point. The patterns of tree ferns will only be revealed when seen from above.

The Soil

Before planting any site, consider the soil type and condition. Often banks are high in clay, or they're sandy. Success on a steep bank can be determined by the quality of the soil. Always add organic matter, compost and mulch the plants in well. If your bank is high in clay, use gypsum to help break this down.

The Plants

Planting is the key. Banks are frequently hot and dry in summer and often only drought-tolerant plants will survive. Some banks are exposed to salt air, and only certain types of plants will cope with these conditions.

Gardening in such an environment can sometimes be made easier by sticking with natives. Many natives, such as grasses, can become fantastic design features and will provide movement in the wind. Add some contrast with mounds of hebe, glossy coprosmas and pachystegia, and include spikes of lancewood and bold flaxes.

Climbing rata and Rengarenga (Arthropodium cirratum) can be used on the bank. Peppermint geranium is an example of an excellent ground cover with scented silver foliage and small white flowers.

Don't think that only natives will cope on a steep bank. Many plants will cope, given the correct soil conditions and shelter and support where possible. Remember to stake taller plants well, and leave them staked for a couple of years to help the roots systems become well established.

The Slope

A hillside garden is not always a disadvantage. Consider changing the level; this can offer you an opportunity to use pathways, steps and terracing to define separate garden areas. It will also mark a transition from one garden `room` to another and can create a feature.

Steps can have ornamental as well as practical purposes. On flat sites, designers frequently create levels, importing soil to do so, or cut and fill on gently sloping sites to create the illusion of a change in levels.

You could use rocks, railway sleepers or other strong but natural looking products to make retaining walls for terracing. Remember to check with your local council about regulations. Reducing the slope in some areas can help with retention of water, making it accessible to the plants roots (rather than just sliding on past), and reducing the amount of soil that is washed away. Terraces need not be the same size or shape. Varying the terraces helps to create different points of focus, and can create an opportunity for a gently winding pathway.

Seating carefully positioned can also help to break up the solidity of a bank, becoming not only a focal point, but perhaps a necessity!

Irrigation and Mulching

Where possible, include irrigation in your plans for the bank. If it is an exposed site, ensure you use dripper type irrigation, or weepy hoses. This will ensure that the plants get the water, not the surrounding environment.

As irrigation on a bank can be complicated by varying pressures from the gradient, it may be best to seek professional advice before you get too far down the track with this step.

Finally, mulch, mulch and mulch some more to help improve soil condition, retain moisture and reduce weeds on the steep bank.