How to be English: a horticultural guide

What is the 'new' English garden? One man takes Emma Townshend on a tour through some of the country's finest spaces to try to answer just that question

The edges of the garden at Pettifers artfully devolve into areas for flowering shrubs and trees such as the pink magnolia (Andrew Lawson)

Can you reinvent the English garden? That's the question posed in a new book by Tim Richardson, The New English Garden (£40, Frances Lincoln). A distinguished landscape and gardens critic, Richardson is the author of many books, and a tireless yet utterly non-boring campaigner for unpaid organisations from the Garden History Society to the Chelsea Fringe Festival. He is also, more informally, the person with whom you most want to wander round a flower show, always ready with a smile, a free promotional badge and a gently different take on things.

He's quick to point out his hopes for his new volume: "I guess I think of the book primarily as a record, a chronicle, of the recent development of a naturalistic planting style," he says. Richardson tracks the way in which that style, in the form of the New Perennial movement led by Dutch gardenmeister Piet Oudolf, has begun to fan out into gardens ranging from little private Pettifers in Oxfordshire (which makes the front cover) to Royal Highgrove in Gloucestershire to state-sponsored eco-planting at the Olympic Park in east London. So, meet the new borders. But are they just the same as the old borders?

The evidence of National Trust favourite Packwood House in Warwickshire is interesting to consider. Packwood is one of those fantastically-handy-for-the-motorway gardens that also happens to be deeply seductive. Centred on a set of antique clipped yews called "The Sermon on the Mount", this 16th-century setting hardly seems the place to find a new approach to the English garden.

Yet, it is here. To my mind, National Trust gardeners do some of the best work I've seen in the past decade, trialling not just new varieties but whole new plants in spectacular summer-bedding displays. Mick Evans, head gardener at Packwood, is no exception. Into this strikingly old-fashioned container has been dropped some astonishingly 21st-century planting, with tall, pink Persicarias and those zinging red ricin plants, Ricinus communis "Impala" – a combination which could be from no other decade than our own. There's a touch of the Scillies in the Aeonium "Schwarzkopf"; and something of Turkey in the massive stands of yellow verbascum.

So there's one vote for the new. And other gardens in the book hint at mould-breaking in an even more exciting way. Though it is rarely open to visitors, Plaz Metaxu in Devon hints at a ferocious reconstruction of the 18th-century landscape garden tradition, which I find more exciting than anything else in the book. It's a bit like what you imagine might've happened had Robert Smithson stayed in Devon in 1969, playing with the Picturesque, rather than going off to Utah to make the Spiral Jetty.

Elsewhere, there's other evidence of just general delectableness. Armscote Manor by Dan Pearson shows all of the designer's customary horticultural knowledge hung on structural backbones of strength and pliability. Glorious stone walls and a peach of a Cotswold manor provide the scenery, where Pearson plays with tradition by providing yew hedges that undulate like green downland.

The hardest thing for a book like this to do is to capture the experience of moving through space that is a garden. Richardson has the advantage of the best garden photographers, Andrew Lawson backed up by Rachel Warne and Jane Sebire. Look at "Wildside", the garden of nurseryman Keith Wiley, and you almost feel like you are taking a walk along its crunching gravel paths, with the soft flowers brushing at your knees. With the help of a mini-digger, Wiley has moved an incredible tonnage of earth to create a gently curving spot for his own wild gardening obsessions, to impressive effect.

There will always be plenty to quibble with in a book on garden design. I personally think that statues of leaping hares should be strictly illegal, but there we go. I'm also never going to be convinced that foxgloves backed by New Covent Garden quantities of rambling pink roses is anything like "New" English gardening; it looks pretty much like the old stuff to me. But that's the fun of going for a walk with Tim Richardson. He's an expert. And he leaves you room to think for yourself. Which is the best possible recommendation for the book, as far as I'm concerned.