Gardens: Helen Dillon's perennially changing floral tapestry

Today, her garden is distinguished by its fresh approach, dynamic feel and the wealth of ideas that keep it from standing still. A garden is no museum: it evolves and is never completely finished. In 1985, inspired by a visit to Morocco, Dillon made the first in a series of changes that astonished friends and visitors - she removed the fountain, thereby converting the pool into a circle of still water. About 10 years later it was the front garden's turn. Dillon felt the house deserved a better setting to enhance its classical Georgian facade. "A house needs to sit down," is how she puts it. Acting on the advice of a friend, landscape architect Feargus McGarvey, she had a retaining wall built parallel to the driveway, steps added and a large area by the front door paved in sandstone. The house now had a dignified entrance. And whereas cars had previously been in full view of the kitchen window, they were now hidden by the wall.

Helen's husband Val compares her garden to a stage with a large cast of extras in the form of "movable" plants in containers. Waiting in the wings are lilies, dahlias, Alstromeria and many others planted in ordinary black plastic pots and metal dustbins, which are unobtrusive and do not compete visually with the plants. "What I love is the impermanence of container gardening," says Dillon. "Bought yet another plant? Can't think where to put it? Simple: buy another pot. With containers a whole new universe is revealed ... If you don't like last year's creation, never do it again."

Colour is one of the most striking aspects of the garden. As Helen Dillon explains, before the changes of 2000 took place, the garden's colour scheme was based on a palette of pastels "that everyone has had for 100 years". Following a visit to Metz in France, where Dillon admired the pretty, silvery municipal flower displays, she decided to switch to a colour scheme resembling an "over-painted picture with a bit of blue thrown in". The finished effect was to look like a packet of Smarties, zinging with primary and secondary candy colours. So, the border on the left of the canal is now reserved mainly for reds and oranges, while the one on the right is predominantly blue and white.

As befits her motto "don't be afraid of orange", Dillon has a succession of different plants on display in this glowing colour. Alstromeria fell out of fashion long ago but has been restored to acceptability by Dillon's use of it as a filler in the hot bed. Opposite, cool shades are provided by bellflowers (Campanula), white valerian (Centranthus ruber "Albus") and noble delphiniums, which are cut back after flowering to bloom again from early July into August.

Dillon is always ready to try a new species even if it ends in tears, as was the case with agave-like Furcraea parmerntieri. For despite the mild winters and a protective covering, this precious plant did not survive, proving that even an experienced gardener can still learn a thing or two.

Trial and error is a hallmark of this garden, as is a willingness to adapt and incorporate new ideas. In 2005 the front garden underwent another makeover, the sandstone paving replaced by larger slabs of light grey Chinese granite and the planting completely altered. Inspired by a three-day train journey between Moscow and Berlin during which Dillon travelled through birchwoods, she decided to plant a strand of filigree Betula "Fascination" underplanted with angel's fishing rods (Dierama) and ornamental grasses such as such as Stipa tenuissima.

Although Helen Dillon yearns for "virgin" soil, hers is a long-established garden with soil that has been worked for over a century. She does her best to replenish it by bringing in tons of cow manure; not particularly elegant, perhaps, but essential if the plants are to flourish. That this is a private garden and not simply for show is also evident from the small vegetable patches casually tucked in behind the delphiniums. As someone open to experiment, Helen remains willing to concede defeat but often opts for a change of tack. After the local fox had finished off the last of the hens, she gave up on that idea. Nowadays, the end of the garden is enlivened by the trilling song from an aviary of bright yellow canaries - the perfect touch in an eclectic garden.

Helen Dillon's garden does not conform to any particular trend and cannot be described as low-maintenance. Her short articles published monthly in The Garden magazine give a flavour of her informative, knowledgeable and witty style. Just like Vita Sackville-West, Helen Dillon writes from experience and from the heart, relating her knowledge and passion for plants. She is always receptive to fresh ideas. As she says herself: "I want to be a creator, not a curator."

This is an edited extract from First Ladies Of Gardening: Pioneers, Designers And Dreamers, by Heidi Howcroft, with photographs by Marianne Majerus, published by Frances Lincoln Ltd, £20