With eight acres at their disposal, Kitty and Daniel Nabarro could have done pretty much anything with their garden. The path they have chosen has involved dividing up the space into a series of outdoor 'rooms' - interconnecting gardens with different themes, separated by hedges, trees and walls.

The effect is delightfully intimate and informal, but at the same time well-controlled. Up by one rustic corner of the house nestles a small, partly paved cottage garden. Nearby there's a gravelled Mediterranean garden and a lavender walk leading to a formal pond. ABeth Chatto inspired perennial garden - glorious in summer - is far enough away from the house not to depress once the petals have fallen. In the distance are paddocks for the horses.

"Neither of us were gardeners when we moved here 14 years ago from a house with a fairly typical suburban garden," says Kitty, a former teacher from Colombia by way of Canada, who is the representative of Totteridge Ward on Barnet Boroughwatch. "But over the years gardening has become our passion."

The couple took their new responsibility seriously, enrolling one day a week for two years at Capel Manor College. They also brought in garden design consultants to help them translate vague ideas into reality. "The garden has just evolved. There was a walled area near the house and we liked that. I don't think this garden lends itself to sloping vistas. It is made up of lots of little rooms.

"We are informal people andwe did notwant anything too showy. We started offworking fairly close to the house and then went further and further." The whole design and planting process took about four years, though as with any garden, things are constantly changing. Today the garden offers a rich and harmonious profusion of colour fromApril through to October.

"Daniel is the ideas person," says Kitty. "He develops the space and I spend a lot of time researching the planting. At first of course, everything was tiny, but I chose the plants according to space and height and I knew how things would look in the end."

This is a garden of contrasts. The tennis court is surrounded by 350 closely planted roses while the area around the large pond - straddled by a bridge made by Daniel in his workshop - looks wild, natural and even haphazard. Nothing, of course, is here by accident. Even the self-seeders are carefully monitored. The current full-time gardener has been with the family for more than ten years.

"One year, Daniel decided we needed a vegetable garden. I decided that we would have a four bed rotation and not use any pesticides." The beautifully laid out vegetable garden - which also provides flowers for the house so that the summer display in the main space need not be disturbed - has raised beds containing brassicas and legumes, alliums and root vegetables. There are also beans, peas, tomatoes, corn, herbs and a large strawberry cage. Against a long wall grow cordoned apples and pears - each tree a different variety. "The soil is rich and we get manure from our horses, which helps. In the summer I buy very few vegetables. We have beans coming out of our ears and I make everything I can think of with courgettes." Friends get some veg, too.

"The garden has changed our lives," says Kitty. "It's made us much more aware of the environment and of nature.My planting is now done according to where something would grow naturally. I will not mix plants from Asia with those from Africa. Some of my planting is based on colour schemes - we have one bed that in autumn is all reds, yellows and oranges - but colour is less important to me than where things come from."

Barbara Elton