BUILD A ROCKERY
1 SELECT your site. Most rockeries do best with at least six hours of direct sunshine a day, but if this is not possible, ensure you choose plants well suited to semi-shade conditions. A sunny slope is good, but by addressing drainage with sharp sand, gravel and rocks, a rockery can also be created on a flat spot beside a driveway or pathway or to the side of a pool or pond.
2 WEED the area thoroughly, and remove any roots or unsightly stumps.
3 BUY or collect your rocks. Aim for an assortment of shapes and sizes. If you don’t have the rocks you need on your own property, look for them in landscape yards. Never remove rocks from native bushland.
4 IMPROVE heavy soils by digging in sharp sand, gypsum and two grades of pumice stone, scoria or pea gravel (left, top). This helps to emulate the natural terrain in which many rockery plants have adapted to grow, and aids air flow around the crown of each plant, reducing the chance of rot. Although many rockery plants don’t require vast, open areas of soil, they do need sharp drainage and oxygen around their roots. This is what gives them ‘the edge’ over many regular garden plants. They thrive in smaller spaces where most other plants would struggle.
5 ARRANGE the rocks to create a variety of levels, heights, cracks and contours. Aim for a natural, random look, and avoid straight lines.
6 ADD a layer of light compost (left, centre) and let it settle into the gaps and cracks. You might choose to wait for the foundations of your rockery to settle over a couple of weeks before you start planting.
7 PLANT UP the rockery (left, bottom). Position taller species, such as dwarf conifers or dwarf acers, at the back. You should be able to view all the plants and rocks at a glance. To save money, fill in crevices with small seasonal annuals such as alyssum, petunia or lobelia in the first year. These will provide quick colour for a low cost, and give you time to invest in longer-term species or wait until seasonal bulbs or specific perennials are available.
8 FINISH with a layer of pumice stone or scoria, which functions as mulch and contrasts with the fine foliage and details of the plants. The lighter the colour of the stone, the better it shows off the plants.