MAKING A ROCK GARDEN.

Otago Daily Times, Issue 19784, 8 May 1926, Page 3

MAKING A ROCK GARDEN.

Written for the Otago Daily Times.

By J. Fleming, F.R.H.S.

There is no need for tho expenditure of much money in making a rock garden, while the actual construction of it can be easily performed by any amateur who has some spare time at his disposal, with the assistance of a jobbing gardener called in for a day or two to perform the heavier part of the work. It is perfectly safe to assure the reader that in the simplest of rock gardens the greater number of the best alpines can he cultivated as successfully as in those built at great cost. In choosing a site for his rock garden, the amateur is usually the victim of circumstances. Almost anv position will do, though an open, sunny one should be chosen if at all available. Drip from trees must be avoided, for very few plants will thrive and look well under such conditions. It is almost immaterial whether the rock garden runs north and south, or cast and west, but it is always desirable to secure a variety of aspects, as plants can be selected for any position The place chosen should be drained, but if underground drainage cannot readily be secured a layer of about nine inches of stones should be p.aced beneath the rockery. This layer may be laid in an excavation of that depth, with an outlet to take away the water, oi on the surface of the ordinary soil. From tho point of view of utility I prefer a porous sandstone, which is able to hold the moisture better than other stones, while plains that object to lime can live on it. But the rockery in which the plants will flourish can be made with any material of tho general nature of stone. Really ugly material can be covered by the plants, and cement slabs, though not desirable, have been the material of which many a beautiful rock garden has been formed. Goodsized pieces of stone are best, but these cannot always be secured. For the mam boclv of the rock garden anv decent soil will do quite well. If the soil is open and moderately light, ail the better. If not. all the more care must he taken wuth that for the roots of the plants. If soil runs short, it may be augmented by putting old bricks, rubble, and pieces of stone among it. The plants will not suffer; they will rather he i-cnefited. For the places where the plants are to ~o there is nothing hotter than two parts of loam, one part of leaf soil, w-ell decayed, and one part of sand. Mix these well together, and for lime-loving plants add some old mortar, such as may be 1 xd from a building which is being demolished. We next come to one of the critical operations, that of laying out the place and putting it into form. If at all possible, the outline should be irregular, broken with little hays and promontories, so as '.o guard against any appearance of formality. There are two ways of proceeding. The one is to lay your stones as the work progresses and fill up with soil. The other, and simpler, is to make your mould of soil first, roughly of the shape _ desired, and then arrange the stones. It is a good plan in either case to lay out the outline with the lower layer of stones or with pegs, and then to fill in the soil behind, raising it to the height desired. If the rock garden is to be of any size, it should be diversified in height, as well as in the general outline. As regards placing the stones, there are several methods. _ What is known as the terrace system is not 60 vdesirable as a more natural et-le. Tho stones are arranged in a series of terraces, with level soil between, and sometimes with other stones placed across these so as to divide the plants. The most pleasing plan, however, is to lay the stones as far as possible in what may be called their natural positions, and to make no attempt at regular terraces. They should be well embedded in the soil, so that, if necessary, they may bo trodden upon without displacement and they must be so laid that they direct the rainfall to the roots of the plants instead of throwing it over the face of the rock garden. This is easily secured bv a little care in placing the stones. The slopes of the garden must not be too steep, and there should : n ail cases ha a good bodv of soil.

For plants which delight in crevices special arrangements may be made, providing for their tastes in almost any parts of the rockery. The soil must be made firm, so that it will not sink afterwards. Finally, no attempt should be made in a small rock garden to imitate the peaks and ravines the Alns. A simple rock garden planned and built in a modest manner is all that is wanted, for it will permit of no cultivation of the most delightful of alpine flowers. Few holidays are so helpful and instructive or so enjoyable to the amateur gardener as a ramble over the mountains, where the exquisite flower treasures that form only small tufts in our rock gardens at home cover the mountainside in the alpine districts of New Zealand.