Designer Mark Bartos has a vision of Provence, that part of southeastern France with a gardening climate so similar to our own. He's imagined walking across fields of sweet lavender, passing through a gap in an ancient stone wall (perhaps from a medieval abbey) to find a grape-covered colonnade with a garden inside.

At its center is an old copper wine-making vat now overflowing with water from some hidden spring. All around it grow shrubby plants with the exquisite foliage--silvers, grays, blues and bronzes--and the soft scents typical of Mediterranean-climate plants.

Under what promises to be a blue Provencal sky, visitors to the Los Angeles Garden Show, co-sponsored by Robinsons-May and the Los Angeles Times, will be able to travel this no-longer imaginary path in "Dreams of Provence," an elaborate display garden created for the show by Pasadena's Hortus Nursery.

The Hortus display is but one of several highly imaginative gardens based on the theme "Gardens of the World" and created in a great flurry of earth-moving and landscaping expertise just days before the show opens Wednesday at the Los Angeles State and County Arboretum.

Display gardens are the highlight of any garden show and some at the Los Angeles show are good enough to take home ribbons from London's fabled Chelsea show. Like the Chelsea exhibits, a few could be lifted up and set down in someone's back yard after the show closes, but most are much too fantastical.

Given the opportunity of creating a garden only meant to last a few days, designers prefer to play and experiment, trying out new materials and unusual plants. Garden shows are a hotbed of new ideas, one reason you may see some visitors taking photographs and notes.

For instance, in "Dreams of Provence," Bartos has experimented with humble materials used in elegant and innovative ways. The capitals atop the rough-hewn wood columns are cleverly made of galvanized metal drain pipes crowned with garden tubs, each planted with cascading grape vines. In an anteroom off the main court, he has used ordinary Italian cypress to make extraordinary garden sculpture--a temple of cypress.

The wildly romantic garden by Sassafras Nursery of Topanga called "A Midsummer Night's Dream" is an outdoor bedroom "with a Gothic kick," according to designer Eric Solberg. Although the idea of sleeping in a garden surrounded by roses is tempting, this garden is really a fantasy.