Ma Hang is a minimum-security facility outside Stanley for mainly first-time offenders, those nearing parole, and elderly prisoners such as Wah. Gardening has long been part of its rehabilitation programme and over the past 17 years Correctional Services Department staff and inmates have contributed a number of prize-winning displays to the annual flower show, which opens on Friday. Last year, their installation of roses and geraniums featuring a replica of Victoria Prison won an award for landscape display.

Tending to plants helps soothe prisoners who inevitably feel restive and frustrated in confinement, says prison superintendent Kenneth Ho Kwong-fai.

A prisoner who wishes to be known only as Shing, sentenced to jail in December for theft, recalls how hard he found life behind bars at first. 'When I was imprisoned, I wasn't assigned any tasks. I was locked in the cell for a week and it was torture. My mind was constantly churning over my problems,' he says.

Gardening took his mind off his troubles, Shing says. 'It keeps me busy. Sometimes I wish I could spend more time in the garden.'

From just hoeing the soil, Shing was put in charge of a small plot that he has filled with a variety of blooms. He may not be able to remember their names, but the pursuit has given the former minibus driver, who had never planted anything until he went to prison, a new outlook. 'I used to vandalise plants in public housing estates just for fun,' he says sheepishly.

Gardening gives him a sense of responsibility because the flowers will be used to brighten up nearby community centres, schools and other prisons. 'If plants in my section die, I feel guilty as my brothers [fellow inmates] put in a lot of work to cultivate them,' he says.

Wah, who has been in jail for six months, feels the same way. 'I felt frustrated when I was first locked up; I thought my life was such a failure,' says the former businessman.

The work not only helps Wah get through long days in jail; he has also discovered a passion for gardening and plans to use the know-how to rebuild his life.

'When I'm released in May, I'll buy a plot on land on the mainland to grow popular plants such as peach and tangerine for sale in Hong Kong. The flower market here is blooming,' he says.

Wah has been doing his homework, avidly reading up on horticulture in the prison library. 'I've started a lot of businesses and all have failed. But I've decided to devote the rest of my life to the flower business.'

The inmates work as part of a disciplined team, Wah says, and work goes on rain or shine, even through last month's cold spell.

Assistant officer Lee Yiu-king says it takes a lot of patience to teach the prisoners to care for the plants. 'They come from all walks of life. Some are enthusiastic because they prefer gardening to tedious chores such as doing the laundry. But there are also some unmotivated prisoners who need closer supervision,' he says.

Lee and other officers will set up the prison's display of 8,000 gerberas, the variety that the show is highlighting, because the convicts aren't allowed out. In keeping with this year's Olympics theme, the gerberas will be arranged in the form of a huge five-petal flower in colours of the interlocking rings logo. A fountain will be at the centre as a symbol of rehabilitation.

The annual show began 22 years ago, with a small exhibition in City Hall featuring mainly flower arrangements. Since then, it has become a major event that includes landscape displays, talks and floral art demonstrations, attracting about 200 local and overseas exhibitors and 500,000 visitors each year.

The show's popularity reflects Hongkongers' greater awareness of greenery and desire for a better quality of life, says Alfred Chow Chi-man of the Institute of Horticulture, a regular exhibitor.

Maggie Yu Yuk-chu, who belongs to African violet and orchid enthusiasts' groups, says a cheaper and more plentiful supply of flowers has also encouraged more people to cultivate pot plants. 'A pot of butterfly orchid is only a quarter of its price 10 years ago,' she says. 'Potted plants are more affordable.'

This year, horticultural therapist Connie Fung Yuen-yee will collaborate with Kadoorie Farm and Botanic Garden to create a sensory path for disabled people and dementia patients at the show.

'The fragrance of mint, vibrant colours of gerberas and velvety texture of lamb's ear leaves are good stimulants,' she says. 'They help people with special needs get connected with the nature.'

Shing is looking forward to checking out the installations; he is being released this week. 'Being in jail was misery. But if there's something I want to remember, it'd be the flowers,' he says. 'When I get out, I'll give myself a few days to settle down. Then I'll go to the flower show. I can't wait to see the fruits of our hard work as a free man.'

Hong Kong Flower Show, Victoria Park, Friday to March 24, 9am-9pm. Admission: HK$14; students and elderly, HK$7. Inquiries: 2697 8030