How to Build Rock Gardens

There are few of us who have not admired the beautiful jewel-like flowers we see growing in rock gardens.

Rock gardening, like growing chrysanthemums or dahlias, is just another specialised form of gardening, one which attracts many gardeners because there are so many delightful plants which can be grown in this way.

When we're interest in how to build rock gardens, there are many things to learn. Rock gardens can be quite small, using a few pieces of stone, covering a few square feet, in which many diminutive plants will flourish, or they may be very extensive with immense rocks and large pockets of soil, in which large plants, including shrubs, are grown.

Fortunately, there is such a wide range of plants that there is no difficulty in finding suitable ones for gardens, great or small. And, although the main flowering period is in the spring, it is possible by choosing plants carefully to have something in flower for practically every week of the year, even in a quite small area.

How to Build Rock Gardens - Making a Rock Garden

A rock garden is not merely a haphazard collection of pieces of rock or lumps of concrete, sticking up at all angles, with pockets of soil in between in which dwarf plants languish. A properly constructed rock garden should, as far as possible, look like a natural outcrop of rocks and give the impression that the rocks seen above the surface are far fewer than those that lie beneath — like an iceberg, which has most of its bulk below water level. To give the right impression it is not necessary to have enormous lumps of stone — quite small pieces are sufficient although if they are available one or two large pieces are helpful to provide the keystones around which the rock garden is built.

To get this naturalistic effect it is best to use stone with well-defined lines or strata. Waterworn Cumberland limestone and certain hard sandstones are the best. Granite and marble are the most unsuitable types. The rocks are laid so that the strata lines run approximately in the same direction. Although this is easier when you build the rock garden on a bank, many successful gardens have been built on the flat. Try to ensure that the garden is built in a series of rough steps and this will leave pockets of soil behind each layer to accommodate plants. These can be filled with lime-free soil for lime-hating plants, peat for peat lovers etc, or you can put in-deep beds of gritty soil for those that like sharp drainage. But ordinary loamy garden soil will do for most alpine plants. Crevices left between the rocks can be used to plant alpines which will create a natural effect. As the plants are supplied in pots it is possible to plant at almost any time of year, even when the plants are in flower. But in the latter case shade them from strong sunshine for a day or two after planting.

Knowing how to build rock gardens can be quite tricky and sometimes technical when it comes to positioning the rocks themselves. Be careful when moving heavy rocks into position or you may injure yourself. When positioning really large ones it is necessary to use a block and tackle and boards. It is important when laying the rocks to make sure that they are seated firmly, packing soil behind and around each one. This will not only prevent the stones wobbling but it will ensure that there are no air pockets into which the roots may penetrate and die.

After the rock garden has been completed it is a good plan to topdress the soil. Where lime-hating plants are being grown peat makes a good topdressing. In fact peat can be used for all plants as it helps to retain moisture and is gradually absorbed into the soil to improve its consistency. If the natural soil is on the heavy side coarse sand can be worked in with a hand fork. Where the natural soil is poor it is best to remove it and replace it with a prepared compost of fibrous loam, moist peat and coarse sand.

Planting between the rocks, must be done carefully with a small trowel or hand fork. Make sure that the soil is firmed evenly. Numerous small shrubs and conifers are suitable for planting on rock gardens and these should be planted first. Do not plant too closely as many alpine plants spread rapidly.