Gardening: Plants with altitude - Part three

You don't have to live on the side of a mountain to appreciate an alpine garden. In the final extract from his book 'Garden Magic', Nigel Colborn shows you how to plan your own

Autumn can be like second spring in a well planned alpine garden. Gentians, in cobalt or kingfisher blue - often with beige and navy stripes on the outsides of their flowers - make a gorgeous contrast with the golds and browns of changing foliage. Where leaves have already fallen, the duns and browns are relieved by patches of wild cyclamen whose pinks and white are cleaner and brighter than fairground coconut ice.

This is the optimum time to dig up pieces of low, creeping plants such as wild thymes or spreading sedums, tearing them into smaller sections - each with a fragment of root - and replanting them to achieve a wider spread of colour next year. Where houseleeks (sempervivums) have become congested, break off individual rosettes, and replant these in either rock crevices or alpine sink gardens.

Bulbs are on sale everywhere and should be planted now, for flowering early next year. Scale is important in an alpine garden, where big daffodils would look ungainly and where small is always beautiful. Look for diminutive, but exquisite, hoop petticoat daffodils (Narcissus bulbocodium) and for such tiny speciess as Crocus chrysanthus, Tulipa tarda and Iris reticulata, to ensure a cheerful overture to spring.

Raised beds, gravel, old stone troughs furnished with mature lichens and an intriguing collection of plants help compose a classic alpine garden. Such important practical considerations as sharp drainage and full light are taken care of in this design. Retained beds and containers, as well as making it easier for the water to run away, enable even the smallest of plants to be enjoyed at close quarters.

Mountain plants may be small - it is often windy high up and they have to keep their heads down! - but what they lack in stature, they make up for in beauty. Some of the most intense colours are to be found among the alpines - the penetrating blues of gentians or the startling cerise of Geranium cinereum - and, in a garden, such plants make a sparkling contribution. Beautiful in habit and flower, many alpine plants form small mounds, whereas others develop ground-hugging mats of foliage and flower.

In this low-profile garden, stone creates the hard structure, backed by high boundary walls and by the taller herbaceous plants - dark tulips and similarly hued bearded irises, with bright yellow asphodeline as a backdrop. The understorey consists of a rich miscellany of alpine plants whose role is to soften the hard surfaces and to "naturalise" the scene. In a natural mountain landscape, exposed rocks and stony screes occur among the plants and an alpine garden looks more attractive and authentic if a similar effect is achieved.

GROUNDWORK Raised beds and containers for alpines need to be free-draining. A layer of broken crocks beneath the compost will assist the drainage in containers; a layer of hardcore and the provision of seepage holes are essential at the base of raised beds. The soil must be porous but should have body and enough nourishment to keep the plants healthy.

PLANTING PROCEDURE The tall plants, which are more suited to lowland conditions, create a lush background which makes a pleasing contrast to the true alpines. Plant tulips at least 10cm (4in) deep in autumn, arranging them in tight groups, with more than about 10cm (4in) between bulbs. The bearded irises and other perennials should also be planted densely, with spacings of up to 30cm (12in).

Plant the saxifrage, Geranium cinereum, thrift and helianthemums close, but not hard up against one another, to show each plant's individual outline. Add at least one winter evergreen per container - here, a dwarf conifer. A dressing of coarse grit reduces the risk of excessive water around the plant necks and improves the appearance of an alpine bed.

MAINTENANCE Control the weeds by hand rather than by hoeing or digging.

PLANTING-BY-NUMBERS PLAN overleaf

PLANT DIRECTORY

Geranium cinereum

A beautiful cranesbill from the Pyrenees, which forms neat rosettes of rounded, deeply lobed foliage, about 20cm by 20cm (8inx8in). In spring and summer, the paIe pink flowers with darker veining will open cup-shaped, but flatten as they mature. Even more spectacular and more vigorous is the Turkish subspecies, G c var subcaulescens, whose flowers are a vivid rosy-magenta.

Helianthemum

Sun rose, rock rose. Low-growing, evergreen shrubs with narrow, simple leaves and terminal sprays of short-lived blooms. Colours range from deep red through pink and yellow to white. Three species, H nummularium, H appeninum and H croceum, have given rise to such hybrids as 'Raspberry Ripple', which is pink and white, 'Mrs C W Earle', a double red, and 'Ben Heckla', which is a startling orange.

Saxifraga (Ligulatae group)

The silver saxifrages have matted rosettes of foliage encrusted with a silvery or limy deposit; in spring and early summer their flowers are carried on showy panicles. Beautiful ones are 'Kathleen Pinsent', whose sprays of flowers are rose-pink, 'Tumbling Waters', which produces huge, arching panicles of white, foamy blossom and 'Southside Seedling', which bears bicoloured pink and white blooms on generous sprays.

Thymus serpyllum

Wild thyme. A mat-forming plant with wiry stems, tiny dark green leaves and, in early summer, a thick covering of small, fragrant, mauve to pink blooms. Evergreen, its foliage may burnish in autumn frosts. Garden forms include 'Pink Chintz' and 'Snowdrift'.

READER OFFER

Nigel Colborn's Garden Magic contains 20 inspiring planting recipes.The book is published by Quadrille at pounds 20, and is available to IoS readers at the special price of pounds 15 (including p&p). To order, simply call the credit card hotline on 01256 302 699 and quote reference GLR 895