Wild thing: The highly structured 'natural' landscapes of Piet Oudolf

Accept death. That's what Piet Oudolf wants you to do. You might imagine a summer garden would be full of lovely flowers, but he has other ideas. Rotting vegetation? Allows you to process emotionally the fact that everything in the end decomposes. Dying brown stalks? Brown is a colour, too, you know.

Thankfully, Oudolf doesn't always dwell on mortality. He's capable of producing gardens with rich pinks and jewel-reds for the heat of July. But even his summeriest creations are qualitatively different from conventional gardens: at RHS Wisley (above), for example, instead of the standard delights of the great English herbaceous border, there are grasses, moving in the slightest breeze, providing a kind of background sheen. There are tall, structural perennials, such as Eryngium and Perovskia, accents of bright green and pale lilac. And there are loose blends of plants from meadows and prairies, giving his gardens their distinctive palette of pale, wheaten hues.

Never mind the prairie at the moment, though. This week, Oudolf has opened one of his very tiniest gardens so far, at the Serpentine Gallery in London. The centrepiece of a mysterious black pavilion designed by the Swiss architect Peter Zumthor, the intention is to provide tranquility and a sort of refuge, for human beings as well as butterflies and bees. Walk inside the black box and find the roof open to the sky, with a cloister to sit and contemplate. The pavilion is open till October, but it's likely to be popular: arrive early for any chance at real peace.

Oudolf's gardens often give the impression of hazy looseness, but in the first serious monograph on his work (Piet Oudolf: Landscapes in Landscapes, £45, Thames & Hudson), published this week, the dedicated student can pick apart the master's designs. It's extraordinary to see quite how structured they are. Richly equipped with plans, colour charts and detailed planting lists, the book is a joy for any gardener who wants to know exactly how Oudolf makes those oceans of daisies look like a swaying sea.

Designs featured range from small private gardens (check out how to tuck a swimming pool into a backyard, Piet style) to a vast plutocratic estate on the exclusive holiday island of Nantucket (complete with tennis "field", guys). Then there are projects familiar to the English garden-goer, such as Wisley and Scampston Hall. And the delightfully unfamiliar, such as Dream Park, Sweden, and Oudolf's home garden, complete with a detailed plan which makes the photos twice as enjoyable to scrutinise.

Oudolf has introduced plants to our palette which were unfamiliar 20 years ago, such as Baptisias and Amsonias; and popularised others such as Echinacea, Rudbeckia and tall, elegant Veronicas. But it's particularly striking to see on paper how the wildness he evokes is underpinned by framework, structure and rhythm: nature held in check by an almost invisible hand.

Oudolf on show

1. Trentham Estate, Staffordshire

In the grand remains of one of the very grandest Victorian gardens, find a 12,000sq m Oudolf landscape. Daring and delightful. Open daily, trentham.co.uk

2. Scampston Hll, north Yorkshire

An elegant walled vegetable garden reworked, set in a Capability Brown landscape. Flowing rivers of grass and minimalist structures alike. Open daily in summer except Monday, scampston.co.uk

3. Pensthorpe nature reserve, Norfolk

Oudolf at his most natural, with hazy drifts galore set among winding gravel paths. And red squirrels. Open daily, pensthorpe.com