Zen and the art of garden design

I have never seen gardening more subtly practised than in the Bloedel Reserve. It is one of my favourite gardens – a veritable enchanted forest, well worth the time and effort that it takes to get there, which is considerable. Reaching it involves going right across the United States to Seattle, over the Puget Sound by ferry and then along the old logging roads to the north-east tip of Bainbridge Island. Once, all this was damp, primeval evergreen forest, massive-trunked Douglas firs, red cedars and hemlocks, black bears and Suquamish Indians. With the white man came comprehensive felling, and one of the largest of the region's lumber companies was built up by a Mr J.H Bloedel.

It was his son, Prentice, who developed the reserve from 1951 until his death, aged 96, in 1996. Although active in the family business in later life, he began his career as a science teacher and had, according to his daughter, an almost mystical feeling for the land and for man's stewardship of it. After buying the 150-acre estate, with its French-style château overlooking the sea, he began exploring the woods, swamps and streams.

"We found the land marvellously varied," he wrote. "We found single plants and colonies of fragile woodland species, mosses, ferns, a world of incomparable diversity. We found that plants often have a way of arranging and disposing themselves with a harmony of colour, texture and form when left to themselves. We discovered that there is a grandeur in decay. Out of these experiences comes an unexpected insight...... One feels the existence of a divine order. Man is not set apart from the rest of nature, he is just a member [of it], a member that nature can do without but who cannot do without nature. One realises that we humans are trustees in this world."

He nurtured much of the estate as wilderness and a refuge for wildlife. He played out his gardening as a sort of dance with nature through a series of forest glades, tapping into the existing landscape, allowing the native plants to colonise and self-sow, but merging them into an aesthetic vision. Some glades are dashingly formal, such as the canal-like Reflection Pool, simply framed by grass and yew hedges, which he developed with the help of his friend, the celebrated Modernist designer Thomas Church.

But in others it is very hard to tell what is natural and what contrived. A rocky stream bubbles down a slope, between moss, boulders and native deer ferns (Blechnum spicant), into a quiet pool. It is a scene that seems to have sprung out of the dark woods, through a web of fallen, lichen-encrusted branches, but there is a perfection in the placement of all the elements that makes you look again. In fact, the boulders have been moved, the water manipulated, the ferns edited and the moss cleaned of leaf litter. The result is as finely tuned as a Japanese garden.

"Bloedel never went to Japan," Richard Brown, the reserve's long-serving director, told me. "But he read a lot and worked with a Japanese designer, and his interest in Japanese gardening pervades the reserve. It influenced the manipulation of the turns and trails, the balancing volumes of open spaces and dense growth, and the sensitive detailing."

The Moss Garden is perhaps the most magical deception, an apparently primeval landscape of decaying alder stumps, punctuated by ferns, huckleberries (vaccinium) and weird Hercules walking-stick trees (Aralia spinosa), all enveloped in a thick lime-green moss. But, again,

the inspiration is Japanese and initially the site had to be cleared of its undergrowth and planted up with 275,000 pots of Irish moss. Eventually native mosses overwhelmed them and the garden was embraced by the forest.

At one point the lime green of the moss meets a river of grey cobbles and grassy black-leaved lily turf (ophiopogon). This is the entrance to the Zen garden, the most self-consciously Eastern glade. A formal rectangle of raked gravel and rock, framed by a chequerboard of moss and pale slabs, it is overlooked by an oriental guesthouse. Japanese gardens outside Japan are rarely convincing, but this one is so serene in its isolated setting – in a climate and vegetation not so far removed from Japan's – that you soon succumb.

The oriental design intensifies the impact of the raw forest, while exotics are used to heighten the shapes and greens of the native plants. Often, there is just a solitary blast of intense seasonal colour from a cherry tree or a drift of witch-hazels. Here and there, displays may connect across a view – rhododendrons with poolside primulas or autumn-tinting shrubs with cyclamen. "But Bloedel was not interested in great exhibitions of colour," says Brown. "And it is always a very fine judgement when we are deciding whether to introduce any non-native species."

One of the most potent contrasts lurks in a dell below the house, where you walk out of the darkness of the tree canopy into a blindingly bright plantation of white-trunked birches. This is a recent – and bold – addition to the reserve and is indicative of the imaginative way it continues to be managed and developed. Bloedel left a generous endowment, so generous that the reserve can function without fund-raising.

Visits must be booked in advance and numbers are restricted so that everyone can properly experience the peace of the garden and the power of the forest. The first time I went I was completely alone, the silence disturbed only by what sounded like rude parps on a wind instrument. These turned out to come from a pair of trumpeter swans living up to their name. Another white apparition against the blackness of forest and water.