ARTS: Not a place for gnomes

HOW much better The Buildings of England is, now that Bridget Cherry, rather than the late Sir Nikolaus Pevsner, is responsible for the series! I love Cherry's recent London: North West, and consulted it before going to the Chelsea Physic Garden - which of course, is scarcely a building, but is still well summarised in Cherry's perambulation of the Royal Hospital Road and Chelsea Embankment area.

It's the "second oldest botanic garden in England," Cherry writes, "founded by the Society of Apothecaries in 1673 and still flourishing. The first curator, John Watts, surrounded the garden with its high walls, divided it into its existing quarters ... The garden reached the height of its fame in the 18th century, when Philip Miller was gardener under the patronage of Sir Hans Sloane, whose statue stands in the centre, a replica of the original of 1737 by Rysbrack. The west quarter is still laid out with long, narrow, `systematic order' beds. The rock garden, the first in England, is an addition of 1772 ..."

On she goes, describing a place of antiquity, charm and ordered scientific purpose. Watts's high walls still make the garden reserved and special. You can hear but not see the traffic along the Embankment. Above, alarming tycoons rattle in and out of Battersea heliport. Within the garden itself, however, all is calmly studious. For those "systematic beds" were laid out in accordance with a taxonomic system now, I understand, largely outmoded, which grouped families of plants together to show their various relations and perhaps an evolutionary system.

Looking at such plants, one instinctively crouches to note their characteristics. So also with the sculptures that now form the Physic Garden's "Natural Settings" exhibition. In the Chelsea enclave are some three dozen pieces of art. They hide among flowers, float on ponds, lurk in greenhouses, cling to shrubs, are formed from pebbles or are inscribed on stones. Most are small. They are all environmental. Thus they reveal rather than announce their nature. They are oddities within the systematic beds, sly little outlaws from the rules of taxonomy. You have to search for them (a map is provided); and having found every piece a visitor will certainly know more about botany and have become more curious about art. For the purpose of the Physic Garden is to explain; and the erratic rule of this show is to provide little sculptural objects that fit within the garden yet are inexplicable.

I enjoyed my heatwave visit last week and so did my nine-year-old boy. But we were fortunate that Stephen Williams took us round the exhibition that he has devised. He pointed out many things we would otherwise have missed, and explained artists' purposes that are really pretty obscure. "Natural Settings" makes a lovely afternoon out for children bored in the holidays, but I recommend that they take a notebook and camera with them. An expedition should allow two hours to see the whole show and to work out what's going on.

A camera, because so many of these little works lack the physical presence that usually makes sculpture linger in the mind's eye. A notebook, because it's all so interesting. Two hours, because the sculptures are so mixed up with the Physic Garden and its plants. If the art in this show were contained within an all-white gallery box, the exhibits would not detain a visitor for more than 15 minutes. The purpose of "Natural Settings" is to take sculpture away from the candid nature of such surroundings. Williams likes the idea that art should not be considered in isolation, that it should mingle with other things in the world.

He's not alone in this view. Two recent exhibitions have used similar tactics. Three years ago a number of sculptors added things to St Pancras station. Last year sculptors and one or two painters were invited to place work side by side with the ancient statuary in the British Museum's Egyptian galleries. The danger of such exhibitions is that the contemporary sculpture can seem merely whimsical, but the artists in the Physic Garden usually avoid this trap. Andrej Syska's Some Flowers For You, for instance, is made of groups of spoons stuck into a lawn, so that they have the appearance of spring bulbs coming into flower. It's just a conceit, maybe; but it isn't silly and is nicely within the spirit of the Chelsea exercise.

Syska, an artist, new to me, lives and works in Poland. The Physic Garden sculptors range from distinguished establishment figures to recent art- school graduates. Shelagh Cluett and Richard Deacon are in the former category. Cluett's Maps Without Territory consists of flat stones with runic markings. The title suggests that her mind is not within the greenhouses that host these stones. Deacon's untitled work almost invites the visitor to name it, for it is more mysterious than Cluett's, yet also seems to be a familiar part of animal or vegetable life. Just a bulbous double form on the surface of a pond: but it cleverly announces an existence halfway between sculpture and nature.

Not many years ago, Deacon's metaphor would have been ruled out by the people who ran the white-box galleries. That was when three-dimensional art was praised for its object-like identity. We liked the way that contemporary sculpture could never be confused with nature. "Natural Settings" begins with the premise that avant-garde sculpture in 1995 can somehow collude with the natural world. Well, obviously it can. But with the loss of sharpness and distinctness, and also, it seems, with a failure of ambition for art.

Nobody in the Physic Garden looks really serious about their work. That's okay in this hot summer, and Stephen Williams is right to detect a public reaction against those pompous "sculpture trails" that force one to walk for miles from one solemn monument to the next. We want something lighter. Certain parodies of nature are attractive. Katya Follett's The Million Petalled Flower of Being is a good thing to block a pathway. Jill Townsley's imitation of fronds and waving stalks has been made from woven aluminium wire. Other pleasant works are contributed by Jo Stockham, Marigold Hodgkinson and Naomi Siderfin.

! "Natural Settings": the Chelsea Physic Garden, 66 Royal Hospital Road, SW3 (0171 352 5646), to 10 Sept. The garden has special opening hours (normally Wed and Sun only) for the public during the run of the show, as follows: Wednesday 2-5pm, Thursday 2-7pm, Sunday 2-6pm. Admission pounds 3.50; students, unemployed and children pounds 1.80.