On a bright autumn day, visitors at the Edenham Day Centre for people with dementia in West Kensington, London, visited a tiny courtyard garden. One man explored a tomato plant, another fingered ivy on the wall, and a woman painted flowers on a bench. They weren't just passing time. They were participating in Britain's latest treatment for Alzheimer's patients: garden therapy.

The idea is that gardening not only improves the quality of life for people suffering from Alzheimer's but also helps alleviate the anxiety that comes with dementia. There isn't abundant scientific evidence that gardening has a lasting effect, but some British health practitioners point to a wealth of anecdotal evidence showing that therapeutic gardens improve patients' moods and cut down on disruptive behavior. The trend is taking off in nursing homes and day centers.

A year ago Edenham's 24-by 24-meter courtyard was a fallow mess, largely unused by patients or staff. Joanna Denham, head support worker, planted fragrant thyme, lavender, mint and lemon verbena, bright flowers like geraniums and the fuzzy-to-the-touch cineraria. "We started having garden activities just once a week," she said. "Now everybody is coming out here every day, and the garden has taken on a life of its own." It's even replaced the TV room as the center of activity.

Denham insists that the gardening has helped patients. "We have a woman who can barely remember how to feed her herself, but one day she came out here and potted plants," she says. "It was remarkable. Perhaps it was feeling the soil which unlocked some memory for her." These results would not surprise Jiska Cohen-Mansfield, research director of the Research Institute on Aging in Washington, D.C. Her 1998 study showed that Alzheimer's patients who visited gardens regularly had less disruptive behavior and improved moods. "I believe that horticultural therapy shows the greatest benefits to those who have found gardening meaningful throughout their lives," she says.

Most therapeutic gardens include an enclosure to prevent patients from wandering off, a circulating fountain, fragrant and bright flowers, and paths shaped in a circle or figure eight (so patients won't get lost). And, for many Alzheimer's patients, being back in the garden means keeping some of their happiest memories.