Obviously you can't wait 200 years for your big baggy monster to occur naturally, but if you're clever you can create a similar look in under 10. To get the sofa effect, you'll need a double line of box plants, as large as you can afford. If you start with them big, that cuts down on the time you have to wait before shaping the hedge. If you buy small ones, a foot or so in height, space them 6in apart. If you get them more mature, jut them up against each other so they touch. This can be expensive - a foot-tall box plant will cost pounds 5 or more.
But if you want to save money and have got lots of time, nothing is easier than growing your own. You need no propagators, no greenhouse, no kit at all. The text books tell you to take semi-ripe cuttings in the summer and early autumn. They'll root more quickly at that time of year, but I've found they root at any time of year except in the depths of winter. Cut a shoot, or even a section more substantial than that. This year, when I pruned my box spheres in late spring, I took cuttings from 3in branched sections, and they rooted in a couple of months. Strip the bottom leaves and push them into their own individual pots filled with a gritty mix of two-thirds multi-purpose potting compost, one third horticultural grit. They will root in a couple of months. Pot them on and feed them with liquid seaweed and they'll be 6in tall in 6 months' time. In three or four years, they should be big enough to clip into any shape.
Box is an easy and cooperative plant. Like yew (Taxus baccata), it has the physical characteristics that allow it to be abused. If you pinch it out in one place, it will bush out somewhere else. By trimming it, you force it to produce buds in the vacant areas and so you can sculpt it into any shape you want. For traditional topiary, you need a frame, plonked over the plant. When first in place, you clip every stem that protrudes through the bars, and then wait for new growth to fill the mould.
For funky box, you don't need a frame. Just go with the flow - have some flat bits, some rounds, large humps and small, like random sand dunes running beside your path. The old hedge around the Belgium designer Jacques Wirtz's garden near Antwerp is probably the most perfect example in the world of box put to this end. It's far from artless. To clip a hedge so that it looks not like a green girder, but a naturally evolving and even breaking form - a kind of horticultural surf - takes enormous skill and a subtle eye. Wirtz found the hedge in a fairly derelict condition and he absorbed it into the garden, not by shutting it into callipers, but by adopting and exaggerating its natural form. You won't have the creases of age in your box hedge, but pick up and exaggerate the difference between each plant. As you walk down the line, you'll see the shapes that they want to be. All you have to do is emphasise that and you'll be there. To keep the curves pronounced, clip twice a year, once in late spring and once in the summer. If you only do it once, do it in late summer.
You don't need to be exclusive about this. In Wirtz's own garden, the romantic extrusion of the ancient hedge sits alongside a menagerie of stricter classical forms. There are spheres, cubes, bells and poodle tails - one lower dome, connected to a sphere by a length of stem. There are cylinders, pyramids and some flat fez shapes too. The two manners enhance each other.
There is a short cut to the classical bit of your topiary garden. By taking this, you won't have to wait for the finished effect - you can buy it off the shelf. If you have the budget, you can instantly select a wide range of different shapes and just place them cheek by jowl. Wirtz packs the different shapes into the space, with little room between them. They jostle, pushed together, rubbing shoulders, exchanging courtesies, insults, jokes. A large globe, 75cm across, will cost about pounds 75.
Wirtz's garden is large, but the scale is irrelevant. You can achieve this effect in a space 10ft square: tight and loose, strict and easy, flatulent and repressed. All of life is here!
Now is a good time to plant, as long as it's not a frosty day. If you plant in the winter, when the ground can be frozen solid for weeks at a time, the new plants may suffer from drought as they try to settle in. The roots will be sitting in ice, not water.
There should be a box revolution. Nothing grows better in the dark, dank and visually sterile spaces which pass for so many peoples' back gardens. Cram them with box and the Wirtz example shows that it does not have to be the garden equivalent of twinset and pearls.
The best book about topiary is Nathaniel Lloyd's `Garden Craftsmanship in yew and box' (Garden Art Press, 1995), which has been republished with a foreword by his son, Christopher Lloyd. For excellent- value box and yew plants contact Chris Gates, Torhill nursery, 01920 823623