Rock Gardens | Rock Gardening

The decorative features of a garden are just as important as its more practical aspects. They lend character and individuality to a layout, and represent an equally sound investment. After all, there are some months of the year when the weather prevents you from making a great deal of use of your outdoor living space. Certainly you can enjoy pursuing the activities of gardening, but you really appreciate having something that is good to look at as you sit in the protection of a warm living room. When the weather does improve, the existence of features such as a pool or rock garden encourages you to go out into the garden and enjoy them at close quarters.

Moreover, if you plan such features in your front garden, they will give pleasure not only to your own family, but to a lot of people who regularly walk — or drive — past your house. We always notice gardens that are attractive and well laid out, and they never cease to give great enjoyment in their own way.

One of the most traditional ways of introducing a decorative feature is in the form of a rock garden. Few people with an average family garden have either the money, space or inclination to build a massive, grand scale rock bank complete with streams and waterfalls, but it is possible to create something equally effective in a small space.

We have all seen rock gardens that don’t work — lumps of concrete dotted about uncomfortably on a mound of earth and weeds. They are best forgotten if you are anxious to find the best way of using rock in your own garden to its full advantage. Remember rather that your pattern should come from stone formations in their natural state. Most of us, while on holiday in the Lake District, Scotland, North Wales or many other parts of Great Britain, have visited beauty spots where rock — and perhaps water — are an essential part of the landscape.

Whether the rock has been beaten to a rugged face or worn pebble smooth by the elements, its appeal seems to lie in the feeling of solidity and permanence that it evokes. It has probably been there for thousands of years. This feeling is one that should be recreated in your garden, and will help to give it an established look.

The appearance of rock in its natural setting can give you further guidelines. Look at the size of the rock pieces; they vary enormously from large chunks to tiny pebbles, and the rock you use should do the same. 1 – 1-1/2 tons should be a sufficient quantity of rock for a small feature, and the pieces should vary in size from, say, 2 to 3cwt to pebbles. However, the majority should, of course, be made up of pieces of a reasonable size in order to create an impact.

You will notice too that the strata of rock is often visible, and that it naturally follows the horizontal line of the earth’s surface. The rock in your garden will look uncomfortably unnatural if you distort the strata line to any great extent, although it can be effective to tilt just one or two stones slightly. If the rock you use comes from moorland rather than a quarry, it will have a weathered face that has been exposed to the elements. This is the face that you want to see in your garden; it will help to give that feeling of a permanent and an established feature.

Having gained an impression of the general desired effect, the decision must be taken as to where your rock garden should be situated. The ideal site is a sunny, gently sloping bank where the soil is not too heavy and there are no large tree roots.

However, if your garden is flat, you can create an artificial bank, which may need to be supported by a retaining wall at the rear. Try to integrate the rock feature into its surroundings if you do this, so that the bank slopes gently to merge with the flatter ground around it rather than simply coming to an abrupt end.

Having decided on the site, you will want to turn your thoughts to selecting the type of rock to use. Prices can vary, and tend to depend a great deal on the transportation costs. It will, therefore, be cheaper to use a rock that is local to your area; there are attractive stones in many parts of the country.

The most familiar is probably the craggy, grey Westmorland rock, which in the south of England is very expensive. A better choice here might be Kent ragstone, with a brownish-buff colour that is easy to blend into almost any garden scheme.

Wherever you live, enquire at your local garden centres and stone merchants and go and look at the rock before you buy. You may even be able to choose exactly the pieces you would like. These will then be weighed, priced and delivered.

Newly quarried rock is often covered in a powdery slurry, but this cleans quite easily if the stone is hosed down.

When it comes to building your rock feature, ensure first that the site is clear of weeds and brickbats. Moving the rock is a job for two people, and pieces can be rolled or levered into position. Keep the site uncluttered and work tidily to avoid accidents. You only have to step back and trip over a large, craggy stone to sustain quite an unpleasant fall.

Start placing the rock at the bottom of the bank, using a large piece as a solid keystone. Build up in, say, three irregular steps to achieve both height and depth. The stones should be bedded securely into the bank, and not perch, wobbling on an edge. If they tilt back slightly a more natural effect will be achieved. The object to bear in mind is that the rock should appear to be the visible part of a much larger underground formation, and should almost seem to ‘grow’ out of its surroundings.

Use the variety of sizes to form outcrops on the edge of your feature, so that the rock is not all clustered in an isolated lump, but blends and fades gradually into the remainder of the garden.

As you position the rock, you will form pockets and cavities between stones. These provide the perfect environment for many small rock and alpine plants, but you should assist by providing a suitable soil. Fill the plant pockets with a mixture of compost and a small quantity of sand. Good drainage is necessary for rock plants and so if the soil in your garden tends to be very heavy, add a little grit or shingle to assist drainage.

Some of the more familiar alpine and rock plants

Most thrive in well drained soil and require a sunny position. They are perennials, and so can be left in the ground to flower every year.

Acaena. An evergreen with bronze tinged leaves — a spreading plant.

Acaena microphylla makes a dense carpet.

Achillea. Yarrow has delicate stems and flattish flower heads, yellow or white, in July to August.

The leaves have a pungent smell.

Alyssum saxatile. This perennial version of the familiar white annual flower has silver foliage and a mass of yellow flowers, which appear in spring.

Anemone x hybrida. A hybrid of the garden flower, known as the Japanese anemone. Flowers, white or pink, appear in late summer — early autumn.

Aubrieta. A favourite garden plant that has a lovely show of tiny blue, pink or mauve flowers in spring.

Campanula. Beautiful miniature bell flowers are in bloom in July to August, and are white, pink or mauve.

Dianthus. Pinks have sweetly scented flowers from June onwards in a wide range of colours.

Gentiana. The brilliant blue flower that is associated with the Swiss alps. Flowers in summer.

Helianthemum. Better known as rock rose; the plant grows quickly and a mass of pink, red, orange or yellow flowers bloom throughout the summer.

Iberis. Candytuft is an evergreen plant with dark green leaves and a mass of white flowers in early summer.

Phlox. The alpine varieties have great appeal, with tiny flowers in a range of pastel and brightly coloured shades. Flowers appear from June onwards.

Primula. Some varieties are suited to open positions and others prefer a damp, shady spot. A wonderful range of colours.

Saxifraga. There are many forms of the dainty saxifrage suitable for the rock garden, and probably one for just about every position and taste.

Sedum. Again a wide variety.

Known as stonecrop, the plants form a dense cushion of succulent leaves and flower in late summer to early autumn.

Sempervivum. The houseleek too has succulent leaves in the form of rosettes. These alone are attractive, being of many different colours, and in addition the plant has flowers that bloom above the dense mass of the plant.

Thymus. Thyme has a mass of tiny evergreen leaves with a subtle aroma, particularly in full sunlight. The golden leafed, lemon scented variety is worth looking out for.

Viola. The lovely little creeping plant. Many varieties flower all through the summer. Although many of these plants are evergreen, and most have brilliant flowers, they are at their best for a comparatively short time of the year. It is, therefore, a good idea to plant a framework of shrubs that will give permanent height and character to your rock feature, particularly as an interesting background.

Suitable background plants are those which have an interesting shape or colouring, such as Acer palmaium ‘Dissectum’. This is a form of the Japanese maple which has finely cut, fresh green leaves that turn a bronze shade in autumn; equally attractive is Acer palmatum ’Dissectum Atropurpureum’, a form with rich, reddish purple leaves. Low growing shrubs with a spreading habit can be grown among the rocks. Suitable plants include hebe, the evergreen shrub also known as veronica, in particular Hebe ‘Carl Teschner’, with violet flowers and Hebe pinguifolia ‘Pagei’, with bluish leaves and white flower spikes. Cytisus x beanii, a low growing form of broom and Genista hispanica (Spanish gorse) are also suitable, as are the varieties of Potentilla fruticosa. Miniature forms of larger shrubs can be interesting additions to the rock garden; a particularly charming plant is Rhododendron impeditum, which grows to just about 10 to 12in in height.

Conifers and rock are, of course, a familiar combination. Varieties that grow slowly to reach a fair size are good as background planting. These include Juniperus scopulorum ‘Skyrocket’, a dramatic, pencil shaped plant, as the name suggests, and Chamaecyparis lawsoniana ‘Ellwoodii’. This plant has dark green foliage, and ‘Ellwood’s Gold’ is a striking yellow colour. For planting in the rock garden itself, it is advisable to choose dwarf or slow growing conifers, as these will never grow so large as to be out of scale and proportion. Picea glauca ‘Albertiana Conica’ may have a large name, but the plant grows to just 3ft tall, and takes many years to do so. It has a cone-like shape hence the term ‘conica’ in its name. Chamaecyparis obtusa ‘Nana Gracilis’ is another good dwarf with rich green foliage arranged in small sprays. For constant golden colour Chamaecyparis lawsoniana ‘Minima Aurea’ is an excellent choice, and is very slow growing, attaining only about 2ft in height in ten years.

When looking for dwarf conifers in a garden centre, do not be tempted to buy plants that simply look small, and are growing in small pots. They may well be very young specimens of much faster growing plants, and it is always advisable to check with a knowledgeable plants-man to ensure that you obtain slow growing specimens suitable for a rock garden.

It is, perhaps, impossible to consider conifers for the rock garden without thinking of heathers, for the two are a natural combination. Most heathers will not grow in limy or chalky soil, particularly the summer flowering varieties. However, Erica cartiea varieties and Erica darleyensis are exceptions, and are valuable additions to any garden. The great advantage of ericas and callunas, which together form the range of heaths and heathers, is that there is a variety to flower at every time of year. This means that by choosing carefully you could have year-round colour. However, it is advisable to avoid planting, say, one plant each often varieties, for the effect will be patchy, and the plants will have little impact. It is better to narrow your choice to, say, three groups of three plants, with colours of flower and foliage that will blend and not clash.

It is worth bearing in mind the fact that although a rock feature involves quite an investment initially, in terms of both money and effort, it can prove very worthwhile in the long term. If you choose conifers, ericas and other shrubs they will require little maintenance once established. If you decide to experiment with flowering rock and alpine plants, their collection and care can become a fascinating hobby. One thing is certain; whatever your aim in creating a rock garden, if you build with care, thought and a touch of artistic flair, the result will be a feature of lasting and increasing beauty.

07. August 2013 by Dave Pinkney
Categories: Fruit Trees | Tags: , | Comments Off on Rock Gardens | Rock Gardening

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