'I was tacking simple black-and-white pictures on walls. One of these images was the flower. I made a silkscreen print of it, and a few hours later I had a pile of flowers in different colours. I decided to glue them up in the city I love, among the concrete and steel. I wanted to share my work with New Yorkers.'

De Feo likes to point out that he's a street artist, not a graffiti artist. The latter work mainly with spray paint and pay much attention to text and typeface. De Feo works with images that he prints on paper and sticks on walls and buildings with paste.

New York graffiti artists introduced him to the possibilities of wall painting when he was a child, he says, but he went on to develop his own approach to street art. 'Artists like Keith Haring and Jean-Michel Basquiat were spawned from graffiti art. We use the streets to create art in a different way.'

De Feo's art works by repetition. His flower image varies in size and colour, but the basic shape remains the same. He also likes the thrill of posting it up in the city - an act that is still illegal. 'I do enjoy the fact that my work breaks the law,' says the artist, who now teaches at a high school in the mornings. 'But let's face it, I'm not robbing banks or holding up stores. It just appeals to the prankster in me.'

He has had some run-ins with the New York Police Department, although the officers are often just confused by his work. 'In New York 17 years ago the cops were like, 'What are you doing?' They just couldn't figure out what I was about. It was actually easy to work, although I did get a summons once.

'My work is easy to understand and it's child-friendly, so I can usually talk myself out of trouble. Cops don't like to have their authority challenged and my pictures don't really do that.'

Still, 'there's a 90-man graffiti taskforce whose job is to track down people like me. They document street art as part of their job - they could probably publish a good art book with their findings'.

Street art is transitory, which is what De Feo likes. 'Street art is ephemeral. The pictures wither away and disappear, and then sprout up again elsewhere. When you see work in the street that is only there for a short period of time, that becomes a magical moment.'

He has also turned his skills to something less controversial: a children's alphabet book, titled Alphabet City: Out on the Streets. Each letter consists of a relevant piece of street art photographed in a location in New York. Parrots and giraffes sit nicely among the city's urban chaos - along with the ubiquitous flower.

'Even when I was a kid, I wanted to make a kids' book. I came up with lots of children's book ideas. But nothing took off. Then it dawned on me - why not marry my street art to a kids' book? Kids always seem to be the ones that notice me working on the streets - adults are too busy getting from A to B. I installed pictures all over the city, from Chinatown to Harlem.'

De Feo's most recent work, however, is not child-friendly. He has been focusing on a long series of emotionally raw self-portraits reminiscent of the work of Francis Bacon. The images are the result of a marital break-up, he says. 'It was a difficult break-up, and I started to paint myself.

'I took the portraits to the streets and pasted them up all over New York. I had friends ringing me up and asking if I was OK. The works were very dark - much different to what I normally do.

'It was definitely part of my healing process. It helped me get through that period and also helped me to become a better painter.'

De Feo has continued to paint self-portraits, although he's now working on other styles of portraiture as well. He's especially proud of a recent portrait of his daughter, Marianna.

Although his work is now shown in galleries, De Feo still likes to take it to the streets.

During a visit to Hong Kong last year, he pasted flowers and self-portraits around the city.

'I was always apprehensive about doing street art in Hong Kong, but I thought I should try,' he says.

'Then the day before I arrived, French street artist Zevs was arrested for painting the Chanel logo on the Armani fa?ade there. That was worrying, as they put him though the wringer. But I got up my courage and put up some flowers and self-portraits anyway.

'It was interesting as Hong Kong is a big jumble of stuff with one thing tacked on top of another thing. The flowers fitted into the environment, but they also stood out - I was surprised how noticeable they were. They cut through the noise.'

De Feo's work can be seen at Hong Kong's No Borders gallery from Thursday. The show, titled Mining for Splinters and Diamonds, coincides with the release of a different kind of street art - a pair of sneakers the artist designed for the show's sponsors, shoemaker RYZ.

But De Feo's heart will always be out on the streets, no matter how many gallery exhibitions he has.

'One of the most fascinating things about street art is that it makes people notice the environment, the neighbourhood. It makes you realise that you're not travelling through it, you're part of it.

'I am a big fan of New York. I have always wanted to be a part of the fabric of New York, and my art helped me to achieve that. It's a literal way of becoming part of the city.'

Mining for Splinters and Diamonds, Mon-Fri, noon-7pm, No Borders Art, 39 Aberdeen St, Central. Inquiries: 2517 6003. Thu to Aug 14