In between working on his new project in Belfast, making plans for an American TV show and planning a novel, Diarmuid Gavin also finds time for numerous good causes.

Owning a garden personally designed by Diarmuid Gavin is usually a luxury afforded only by the rich and famous, but now as well as a little bit of history, residents of Belfast's newest apartment block — The Bakery on the city's Ormeau Road — will be able to enjoy an outdoor space created by the man himself.

“This is the sort of project I really love getting my hands on,” says the maverick horticulturist and TV star. “I'm a regular visitor to Belfast and I knew two of the lads who were involved in buying the building. Once they told me about its amazing heritage, I jumped at the chance to get involved.

“Wherever I went in Belfast and beyond, everyone I talked to had a story to tell about the Ormeau Bakery — members of their family that worked there, or simply their love of an Ormo loaf. Most people in the city have some connection or memory with the place.

“It was important to do it justice so I spent a long time thinking about what I was going to do and studying old archives and photographs of delivery vans and ovens as it was vital to make the design relevant as well as contemporary.

“After trying out lots of ideas, we decided on a central courtyard filled with low, coloured beds, beautiful planting and a glass bridge which divides different areas. I loved doing it and I've really enjoyed my time in Belfast.

“I've always been shocked by the friendliness of the city. Down south we think we have really friendly people —and we do — but the Northern people take it to a new level.

“Just a few weeks ago, I was strolling down Ormeau Road and people were coming out and inviting me into their shops to see this and to chat about that. It was extraordinary.”

The second of five children, Diarmuid (45) grew up in the Rathfarmham area of Dublin and went to Templeogue College. Although he enjoyed a very happy and secure family life, his schooldays don't hold any happy memories.

“We were by no means rich,” he says of his childhood. “Mum was a housewife and dad was a personnel manager and they both worked very hard for their kids and put a lot into giving us a better life.

“As a kid, I was very much a loner and a bit of a dreamer,” he reveals. “I wasn't particularly social and didn't have loads of mates. I didn't enjoy school at all and was glad when it was over.

“I was always interested in landscaping, though and remember as a boy taking my dad's tools to a nearby park and trying to change a bit of it,” he laughs.

“When I left school at 18, I decided that I either wanted to be a chef or a gardener and worked in a restaurant for a couple of months, which I loved. Then a job came up in a plant shop in Dublin city centre. After three years there and on my second attempt, I was accepted on to a degree course at the College of Amenity Horticulture at Botanic Gardens in Glasnevin, Dublin.”

After graduating Diarmuid set up his own business, but found his creativity stifled by the then trend for conventionally-pretty gardens and, by his own admission, he temporarily lost interest and let things slide.

“I'm not particularly business-minded and if the projects didn't interest me, I couldn't be bothered. I let a lot of people down during those times and I regret that now.

“I always had a dream of what I wanted to do, even if nobody else believed that I could do it. At that time, I was a bit of a laughing stock among the gang I hung around with.”

High-profile horticulture shows were the one place where Diarmuid could let his unconventional ideas run riot and the turning point in his career — there were two in fact — came when he achieved major success at the RDS Flower Show (winning the Gold Award for garden design in 1991 and 1993) and secondly, when he became acquainted with his future wife, Justine Keane.

He met Justine, daughter of former Chief Justice of Ireland Ronan Keane and the late journalist Terry Keane, when he was employed as a gardener by Terry.

“Although I met Justine immediately, it was 18 months before we started dating,” he says. “She turned my life around and I was amazed because this wonderful woman believed in me and encouraged me.

“I must have rubbed of a bit on her too though because when we met she was a psychologist, but then she went and trained at my old college and now works with me,” he laughs.

As he was by his own admission a bit of a Jack-the-lad at the time he met Justine, was he not a bit daunted and nervous at the prospect of dating the daughter of such well-known Irish establishment figures?

“It most certainly was daunting at the start,” he says. “But they were such a nice family. The sort of people who, if they were having friends round for dinner or drinks, everyone from the next door neighbour to the dustman was invited. They made me feel very welcome.”

The couple were married in 1995 and now live in Kilmacanogue, Co Wicklow, with their four-year-old daughter, Eppie.

Encouraged by Justine, Diarmuid entered and won the bronze medal at the 1995 Royal Horticultural Society Chelsea Flower Show. The following year his modern and vibrant city garden caused quite a stir and led to him being spotted by TV producers and the BBC series, Diarmuid's Big Adventure.

Much more television followed including, Gardeners' World and the hugely-popular Home Front, which he co-presented with Laurence Llewelyn-Bowen. Now, he is also the author of nine books and is a much-in-demand lecturer all over the world. And in 2004 and 2007, he scooped the silver-gilt medal at Chelsea.

His business is now so successful that he has offices in both Dublin and London and regularly collaborates with Sir Terence Conran. He has designed gardens for stars including members of U2, Sophie Ellis-Bextor, Jodie Kidd and rugby hero Lawrence Dallaglio. But Diarmuid reveals that his father still can't quite believe that this once-wayward son has finally made something of himself.

“When I first started, mum and dad were relieved that I wanted to work at anything at all,” he laughs. “They had always hoped I would get a good pensionable job in a bank or something, so when I went into gardening they were demented with worry. Having been a bit of a black sheep they are still amazed that anything ever became of me.

“It was my birthday a couple of weeks ago and I got a card from my dad with a £50 pound note in it. I think he still feels that I need a little help,” he jokes. “Underneath it all though, I know they're proud of me.”

As well as gardening programmes, Diarmuid has also done his fair share of reality TV. He has appeared on The Weakest Link and Mastermind and has also been a contestant on Strictly Come Dancing in 2004 and Only Fools on Horses in 2006 — a programme that resulted in the IFTA-award-winning RTE series Diarmuid's Pony Kids, where children from disadvantaged areas who ride in fields on urban estates were trained by equestrian experts, including Zara Phillips, on how to showjump.

“Once you are half well-known, you tend to get offered everything and I've always been really fussy and only agreed to do shows which would teach me skills that I've always been intrigued by,” he says.

“Strictly was great fun, but I absolutely loved doing Only Fools on Horses and that's the one skill I've kept up. Pony Kids was amazing and I'm still involved in that project.”

After the launch of The Bakery, Diarmuid's off to the States and he reveals that there's also a novel in the offing.

“I've had a few enquiries from America so after Ormeau, Justine, Eppie and I are going to live in California for a few months. The people behind American Idol have written a programme about gardening and they've asked me to come out for talks. Eppie starts school later this year, so it's the ideal time to spend some time in America.

“I've also started working on a murder mystery set at the Chelsea Flower Show,” he laughs. “The idea came from a little-seen reality-type show made by the BBC, where a group of people had to write a play or novel. The idea has stayed with me and I'm going to keep at it and see where it goes — not this year though, I'm far too busy.”

Like a lot of successful people who can't quite believe their own good luck, Diarmuid spends as much time as he can giving something back and as well as Pony Kids, he also spends a lot of time getting his hands dirty on building sites in South Africa.

“I'm very involved with the Niall Mellon Township Trust, which was established eight years ago to provide housing for impoverished communities in the townships of South Africa,” he says.

The only thing he doesn't enjoy about his success is the heart-throb status he's acquired since he became a household name.

“It's all rather silly, isn't it,” he says sounding distinctly uncomfortable. “I'm just a gardener who had a dream and who was in the right place at the right time. It could easily have gone the other way... and it very nearly did.”