Michael Coleman's paintings of the Phoenix Park reflect its natural setting but also its more tawdry aspects, he tells Aidan Dunne

The paintings in Michael Coleman's exhibition Hearts & Trees at the Cross Gallery arise out of an unusual residency. For close on three years, he has occupied a studio in the Phoenix Park in Dublin, and the work he has made there reflects the surroundings, if not quite in the way you might expect. His view of the park is complex, even to some degree ambivalent.

Coleman, who lives in the Liberties, is Dublin-born. A youthful 55, he observes the world with a wry smile and a relaxed, bookish manner. "I've known the park since I was a kid, and I wanted to make work about it." A few years ago he happened to meet John McCullen, the park's superintendent. "Originally I approached him thinking that there might be somewhere I could store work. He came back to me and said: 'Look, we happen to have this building . . .' "

The small, modern octagonal structure, close to the Knockmaroon Gate and the Furry Glen, is a disused information centre. "It had been empty for years." It is not an obvious studio. For one thing, its panoramic sweep of full-length windows means that occupants are effectively on display to the outside world. "That was very strange," Coleman admits. But he got used to it. While the front of the building faces onto Knockmaroon Road, the back reveals a different aspect entirely, with an extensive stretch of mature woodland as the land falls away toward the Glen Pond and the Furry Glen.

"As soon as you go through the gates into the park," Coleman notes, "You are in a whole other world."

This is so partly because, as every Dubliner likes to boast, the Phoenix Park is the largest enclosed city park in Europe. The sheer scale of the place is amazing. "What immediately impressed me was the extent to which people use the park. It's a universe of activity and actually, although I visited it as a child and thought I knew it, I've realised that I had only the most superficial experience of it, really."

Apart from the considerable through traffic, and such well-known landmarks as the Ordnance Survey, the Papal Cross and Áras an Uachtaráin: "People really use the park in every way, I mean obviously in terms of sports, and running and horse riding, walking the dog and just walking, picnicking, hanging out - for homeless people, for example, it provides a kind of refuge. It fulfils a need in the city to have somewhere to go, including for people who are desperate in one way or another. There are many layers to it all, and it's well known that this area of the park is associated with clandestine activity. It's a destination for courting couples, and for other sexual encounters."

His paintings distil the various layers into simplified, codified images. "The hearts and trees are two aspects of the park with everything in between implied. The trees are largely what the park is about; they are magnificent. If you go for a walk it's pretty striking how often hearts are cut into the bark of trees, these declarations of love. They are everywhere. But it occurred to me that this place is not merely about declarations of love, there is also the activity in its various shadings. You have the sweetness of the sentiment, but also the physicality."

Coleman spent time in Austria in the past. "I found there is this Middle-European thing of quaintness edged with something darker, a fairytale quality. Hansel and Gretel and the witch in the woods. So we have the birds singing, the leaves rustling, the herds of deer, and it's all true, it's not a deception, it makes a pretty picture. But there's something else as well, something hidden. It reminded me of the way fairy tales mingle the sweet and the sinister. You wander through this apparently natural setting, but of course it's an urban park. There are used condoms and popper bottles littering the ground." The paintings synthesise these contradictory properties.

Simplified accounts of trees and hearts are rendered in lush, warm colours, but the canvases are for the most part jaggedly trimmed and heavily over-painted, and they are tacked roughly to their supports: there is a definite tawdriness underlying the candy colours. "I'm not trying to define anything, really, it's more an attempt to pick up on the subtleties of the atmosphere." There is a straightforward quality to the way the paintings are made that he describes as being "almost naive. I mean, I don't think I am naive, but there's a certain guileless air to them."

For most of his career, Coleman has been best known as an exceptionally rigorous painter of usually monochromatic abstracts, built up from layers of colour and often, though by no means invariably, culminating in coats of thick, intractable pigment, whether black - something of a trademark - but also blue, red, green or pink. But he never settled into a minimalist style as such. There was always an unpredictable, volatile quality to his approach that manifested itself in various ways: in radically reworking exhibitions during the course of their run, or in dispensing with whole bodies of work by painting over them. Several years ago he effected a surprising change of gear when he produced a set of representational landscapes depicting parts of Dublin he encountered every day. These were gentle, anecdotal, affectionate studies.

Why the change? "Well in a way it wasn't a change," he suggests. "I mean, I never know what I'm going to do next. I will embark on something and feel I'm going nowhere, which is fine because that's exactly where I want to go. I think I took monochrome painting very far and very fast when I was relatively young. And monochrome paintings can be marvellous, but unless you have a real reason for making them they can also be flat and decorative."

He cites the American painter Jasper Johns, whose early work is canonical but whose later, more overtly autobiographical, work is more critically contested. "I happen to prefer his early work, but I remember reading an interview in which he said that he was repressed when he made those early paintings. He was keeping things under wraps, under control. I can completely relate to that. All those hidden layers of colour I was building up were about keeping things contained."

So the Dublin studies were in a sense a liberation. Made in wash on paper, they featured no opaque layers, everything was on the surface. Despite their evident layers and their spare, formalised pictorial vocabulary, the Hearts & Trees consolidate this trend. "Talking now as a gay man, it seems to me that in this work I was somehow able to connect with aspects of my younger self that had never been fully realised or resolved. It was like going back to myself as a much younger person; in some way I could tap into what I didn't manage to live through. That was quite strange. I feel I've never exposed this much of myself in my work before."

The studio is liberally stained with paint and littered with torn photographic scraps. "It can be messy," Coleman says sheepishly. "It takes a long time. I find I have to build up a lot before breaking down, I need the time to surround myself with mistakes, with a certain amount of chaos, before I can pare it down to perhaps very little. I mean, if you are sufficiently rigorous, if you are really hard on yourself, you could make a mountain of work and end up with one piece or even with nothing at all."

He narrows his eyes and looks critically at a painting as if it might not come up to scratch. He sighs. "I sometimes wonder if people realise that."

Michael Coleman's Hearts & Trees is at the Cross Gallery, 59 Francis Street, Dublin, until Feb 10