Rockery Garden and Rock Landscaping Ideas
The Rock Garden
Nothing sets off plants better than an environment similar to their natural habitat, but it is not necessary to have a rock garden to grow rock garden plants. Given plenty of space and suitable rocks, this is undoubtedly the ideal, but many people lacking these have to compromise. If you haven’t the energy, time or money to make an impressive rock garden, or the garden is too small, don’t despair – other options are open, such as or sink gardens.
Unless you have the right site for a proper rock landscaping garden, it may be best to settle for one of the alternatives. Where a suitable spot is available, however, a well-planned rock garden can become a superb feature.
Building a Rockery Garden
The first requirement is a sunny, open site, well clear of overhanging trees. A great asset is a sloping site, for this makes construction easier and the finished result more natural.
Good drainage is also vital, so unless the ground is naturally free-draining, be prepared to excavate the site to at least 30cm (1ft), incorporating plenty of coarse drainage material.
Unless there is a natural slope, it will be necessary to build up a good depth ofat the back to give height to the garden. Do not underestimate the amount of soil required, and if you intend growing lime-hating alpines, check the pH before you use it.
For the soil to pack around the rocks it is best to mix a special, and a good one is three parts of loam (well-rotted turves or good garden soil), two parts moss peat, and one-and-a-half parts sharp sand or grit.
Positioning the Rocks
Avoid the temptation to make a little rock go a long way by positioning with the maximum exposed surface, regardless of the shape of the stone. Often more should be buried than exposed, with the rock being set well back into the soil, sloping slightly backwards. Try to arrange the ‘grain’ to follow the same contour in each rock, and set them in tiers with pockets of soil in between.
Rock Landscaping Alternatives
Charming little rockeries can be made in old sinks – raised on bricks for easy tending – or suitable plants can be grown between courses of bricks or paving in a dry wall. Quite a lot of plants can be grown in a space no bigger than a couple of garden frames. The trick is to go upwards, making a firm foundation and setting each piece of stone securely with soil between, and making the top narrower than the base.
One advantage of this method ofis the ability to look after plants like lewisias and rhodohypoxis, which must have sharp drainage. To protect them from winter snow or excessive wet, a frame light or a sheet of polythene can be laid over the top, held clear of the plant.
Another idea is to edge borders and drives with several layers of stone blocks, leaving spaces at intervals for introducing plants, or they can be grown in pockets made in flat crazy-paving. The latter provides an ideal site for carpeting plants such as thyme and aubrietia.
One well-known alpine enthusiast turned his long, narrow suburban garden into a ravine taller than himself. The soil was excavated and thrown up each side of a winding path, rock pockets were then made and filled with good soil, also nooks and crevices, and even a small pool. Here he grew hundreds of rock plants, common and rare, difficult and easy, shade lovers and sun worshippers.
When planting rock garden plants, go for small compact specimens rather than large ones, and turn them from their pots carefully, retaining a ball of soil round the roots. Bare-root plants take much longer to establish.
Prevent damp lying near the surface (it can cause the lower leaves of plants like androsaces and cushion saxifrages to rot, and also encourages worms) by top-dressing the soil between such plants with granite chippings, fine shingle or pot shards. Always plant firmly.
Plants for Particular Situations
Shade lovers are few, but plants like haberleas and ramondas prefer shade, and because they form flat rosettes of foliage are best grown in a vertical position between rocks. Shade lovers for flat positions include the small slipper flowers (Calceolaria biflora), the spring-blooming windflower (Anemone Nemorosa) in its various forms, the heather-like cassiopes; blue, pink or white anemone-like hepaticas, trilliums, shortias, and most alpine primulas. The majority of these also thrive in sun or partial shade in the colder parts of Britain if they have abundant water during the growing season.
Lime-haters must be avoided if you garden on chalk, or they must be confined in some form of container with suitable compost.
On peaty soils, however, treasures such as the lovely blue-trumpeted autumn gentian (Gentiana sino-ornata) can be grown. Others include the twin flower (Linnaea borealis), a genus named after the Swedish naturalist Linne, and most heaths and their near relatives the daboecias, cassiopes, rock jasmine (Androsace carnea), the dwarf, long-flowering pink-and-white Rhodohypoxis baurii, and some irises.
Soils and climate vary so much that it is impossible to lay down hard and fast rules for rock plant cultivation. However, if the soil is gravelly it will require additions of loam and leaf-mould or peat in the planting pockets. Sandy peats and sands also need loam to give them body, plus some limestone chippings for good drainage (except where lime-hating plants are to be grown).
The rocks, too, have a function beyond holding soil in place and presenting a pleasing appearance; they keep roots cool in summer and retain moisture beneath them in hot, dry summers.
Beyond the right soil and rock landscaping site, little attention is needed apart from tidying the plants after flowering. In the case of strong carpeters like alyssum, perennial candytuft (sempervirens) and aubrietia, it is necessary to cut back old growth to about 15cm (6in) with shears. This will keep the plants compact and encourage strong new shoots to carry the next year’s flowers.
Weeds are not likely to be a problem once the plants are growing well, but in the early days it is important to preventbecoming established.
Slugs and snails are the most likely pests, but these are easily controlled with a suitable bait.
Feeding is usually confined to a light dressing of bonemeal applied in spring and again in the autumn.