Billy Carruthers walked into the derelict walled garden of Sue Ryder's Binny Estate three years ago and thought he had ''died and gone to heaven''.

In his boyhood, when he was confined to home in a Glasgow semi, because of his asthma, he developed a love of plants. In the eighties, when he lived in a London flat and owned a chain of successful record shops specialising in imported American music, this love was sustained by trips to Wisley and Kew.

It was only when he came back to Scotland and was looking for a cottage in Ecclesmachan, West Lothian, that he discovered the garden and its amazing potential.

Carruthers now lives in the gardener's cottage on the estate and owns the nursery in the walled garden. It specialises in ornamental grasses (with 120 it's the largest selection in Scotland), unusual herbaceous perennials, ferns (about 20), Euphorbias, rare shrubs and a small selection of alpines.

Carruthers, who is 46 and self-taught, says: ''What you don't know, you can always ask an expert.'' He has been inspired by Karl Foerster, the German nurseryman, plant breeder, gardener and author, whose work earlier this century featured in this month's issue of RHS magazine, The Garden.

Like Foerster, Carruthers recognises the potential of grasses in the garden for their grace and for their winter form which extends interest throughout the seasons. He is creating a show garden at the Binny Estate and finds that a gravel garden lends itself to specimen planting and especially grasses. The shape and form of plants are more important to him than flowers - hence his interest in Euphorbias.

Like Foerster and the Dutch Piet Oudolf and Tonter Linden, Carruthers is trying to break away from the extreme artifice, tired patterns and high maintenance of the traditional lawn and flower garden and to move to a wilder garden ''where the plants rule''.

This year Carruthers' space at the garden show will illustrate how foliage can be used to provide the main interest in a display.

Colours are contrasted in the leaves. Half the planting will be yellows and greens, with some in pots round an area of staging. The grasses in this part of the display will evoke an atmosphere of peace and relaxation.

The other half of the display will incorporate a water feature over rocks with more sedges and the feeling of a wilder garden, that is somewhat neglected. Here large-leafed perennials will be planted beside grasses showing how they can contrast and complement each other. Wild flowers and shade loving plants will be interwoven with different surfaces, including broken paving and gravel, in this forgotten garden.

The display is eye-catching and many of the individual plants merit more than a second glance. For some of them are usually only seen in magazines or glossy gardening books.

Carruthers' perennials include Ligularias, Tiarellas, Heucheras (some with deep blood-red leaves), large leafed perennials such as the Chatham Island forget-me-not, Farfugium japonicum ''Chris Patum'' with its crispy-edged leaves and the lovely little Viola dissecta with coppery leaves and white-scented flowers.

Also, he has the wonderful shamrock Trifolium repens ''Green Ice'' which has clover leaves with a silver band and white flowers. There is the tantalising silver-leafed sorrel Rhumex scutatus ''Silver Shield'' which is - apparently - very tasty.

Carruthers' favourite of his many Euphorbias is ''Excalibur'' with lovely claret-red stems, grey leaves and lime green floral bracts. One which is in great demand - and is much admired in its site behind the Alpine House at the Royal Botanic Garden, Edinburgh - is the dramatic Euphorbia characias wulfenii ''John Tomlinson''.

The scale of Binny Plants' vast selection of grasses, sedges and bamboo will be reflected in the display at the show - there's the tactile Stipa tenuissima or tenuifolia with its fine long arching leaves which sway in the breeze; Elymus magellanicus with intense grey-blue lax leaves which is a good accent plant; and Eragrostis trichodes which has spectacular flower heads and grows up to one metre.

The nursery at the Walled Garden, Binny Estate, Ecclesmachan, Uphall, West Lothian is open every day 10am to 5pm, except Tuesday and Wednesday.