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Creating A Rock Garden...

Posted on 15 March, 2017 at 21:55

A rock garden can be a stunning feature in any garden. The options are endless, they can be small enough to fit into a large container, or big enough to cover a substantial part of the garden. Correctly built and planted, they rarely get out of hand and are easy to maintain. With carefully placed dwarf conifers, interesting rocks and every crevice filled with tiny, creeping, tufted or drooping alpine plants, a miniature landscape can be created which will be a constant source of pleasure.

Rock gardens must be in open sun and the drainage perfect. They cannot succeed in the shade. Even the dappled conditions of an overhanging tree, with plenty of good light, can be a disaster for some alpine plants. The destructive drip of moisture from above means a lingering death for these normally tough plants.

Slopes are a great advantage when building a rock garden, but the soil in flat areas can be built up into an irregular mound or two to increase the planting area and improve drainage. One of the most effective I have seen was on both sides of a garden path which became a winding valley between two superbly-planted mountains.

The secret of success lies in the soil mixture. Most rock plants originate in alpine areas and grow in a mixture of small stones, decayed plant material and little soil. These tiny mountain plants develop a long root-run, well-protected from excess heat and cold. Good quality garden soil, relatively free from clay, with large quantities of fine road metal mixed into it is ideal. These small stones can form up to fifty per cent of the total volume. If generous amounts of granulated peat-moss are also added, the final mixture should resemble the enriched scree in which alpine plants naturally grow.

The advantages of this mixture are: water-holding capacity, easy handling, coolness and easy weeding. After the soil has been prepared it can be moulded into a flat-topped mound, perhaps with an off-centre saddle. Any perennial weeds or clods should have been removed during the mixing. If the soil is acidic, dolomite-limestone at a rate of a double handful to the square metre can be worked into the top thirty centimetres. Old pulverised animal manure and blood and bone can also be added.

The rocks should be as large as it is possible to handle. Small rocks are of little value because they always appear insignificant. If the large rocks are also weather-worn and covered with lichen and moss, they will add enormously to the character of the garden. However, even freshly-spalled quarried stones can be used because the plants will soften their angular shapes. If the water in which potatoes, rice or even spaghetti have been boiled is allowed to cool, then sprayed or painted on to the surface of bare rocks, lichens will soon appear, along with other primitive forms of life.

The aim, when placing the rocks, is to try to imitate natural rock formations. Try to aviod the 'plum-pudding' look by locating the rocks in clusters, obviously relating to each other. Above all, don't stick a group of pointed rocks on the top of the heap, unless that's where your taste lies. We must cheat a little when trying to duplicate nature, by ensuring that all gaps and crevices are wide enough to insert a hand or trowel into. Placing rocks in a new rock garden is also creating spaces and bays for the plants. Above all, try to keep the 'face' that is the most attractive side of the rock, upwards, and lay flat rocks down to allow creeping plants to take them over, rather than having them balanced precariously on their edges.

Once the rocks are in position and secure, the soil between them can be smoothed and then mulched. However, unlike other parts of the garden, alpine gardens are not mulched with pine-bark or woodchips. Organic materials like this will eventually cause the death of many of the plants. The mulch to use is fine bluemetal screenings or similar, spread to a thickness of about five centimetres. This will allow air to circulate around the sensitive base of the plants, while suppressing weeds and sealing in moisture. After forming the garden, fertilize with blood and bone and, if the soil is acidic, add a good handful of dolomite-limestone to each square metre of the surface, then water well.

If there is a rule about planting a rock garden it is this; avoid those plants which have large leaves. They make rocks appear small and the whole effect can be lost. Use small-leaved plants, such as dwarf conifers, low down the sides. Fortunately, rock and alpine plants are still inexpensive and many are easily propagated. Some garden centres have a special section, devoted to these plants, although care must be taken to choose non-invasive species. Crevice lovers like the androsaces form into tiny tussocks which produce pink or white primrose-like flowers. Alpine asters, campanulas, prostrate silvery-leaved chrysanthemums, diminutive brooms, daphne and a whole range of clove-scented alpine pinks are all easily available.

In addition there are many bulbs, corms and tubers sutiable for colonizing pockets in a rock garden, some growing to perfection in the sharply-drained soil. So there you have it, some tips on how to create your own rock garden. Give it a go! You'll be surprised how quick you will get the hang of it...

Categories: Garden And Landscaping