Into the long grass: Alive with insects and bursting with colour - a meadow in flower is a spectacular sight

I've just come back in from fighting hogweed in Foxpatch. The battle has been going on since we arrived here and first started to let the grass grow long in this half-acre plot. Each summer for the past seven years, we've cut off the hogweed flower heads to prevent it seeding. Every week, from early June onwards, I take off more than 200 of the wretched things. And each year the hogweeds come back. This is the reality of trying to manage a "meadow". The bullies are always trying to muscle in.

Poppies and cornflowers have nothing to do with meadows. They are opportunistic annuals, flowers of ploughed land, where each year they race with the corn so that they can flower and set seed before they are overpowered by the surrounding crop. They grow only where the ground is regularly disturbed, the antithesis of a meadow.

You can get pretty effects in a garden by sowing mixes of these annuals in spring, but you'll still find weeds trying to take over. And the show, spectacular in the first half of summer, will be over in the second half as the plants settle to the (to them) more important business of ripening their seed.

I saw some spectacular meadows in June, but none had been started from seed. They had all grown up from areas that had previously been lawn. That is not to say that all lawns will produce good meadows. New lawns are unlikely to be made of the right kind of grass. And they will perhaps have been fed and weed-killed. The best meadows rise up from rather thin ground.

To most of us, grass is grass, but there are actually more than 150 different kinds and since most proper meadows will be 80 per cent grass and 20 per cent flowers, it matters to have the right kinds. You want various kinds of bents (Agrostis canina or Agrostis tenuis), crested dog's tail, sheep's fescue, meadow foxtail. You do not want rye or cock's foot.

If the matrix is of the right kind of grasses, all sorts of other stuff will start appearing: f purple knapweed, yellow hawkweed (Hieraceum), vetches both red and magenta, beautiful rusty-coloured sorrel, low-growing bird's foot trefoil, red and white clover. The clover gives a good indication of the stage the meadow is at. White clover (Trifolium repens) thrives on a regime of close mowing – as lawn fanatics know to their cost. But as grass grows longer, the red clover (Trifolium pratense) starts to take over. The clue lies in their names. Repens describes creeping plants. Pratense describes plants most likely to be found in a meadow.

At Great Dixter, the late Christopher Lloyd's garden in Sussex, the topiary lawn below the house, once close mown, is now a most beautiful meadow. Christopher and Fergus Garrett, the brilliant head gardener, just decided to let the grass grow and see what happened. That was more than 10 years ago and it looks spectacular, the feathery, bronze-mauve flowering heads of the various grasses, waving in a soft veil around the dark, sculptural clipped yews.

It's now richly colonised by orchids, mostly the pale pink cylinders of the common spotted orchid (Dactylorhiza fuchsii), which Christopher supposed must have blown in from other parts of the garden. But the life cycle of wild orchids is mysterious. They do not come up in the same places each year, yet they are not annuals. What are they doing while they are underground? What conditions do they need to flourish?

The topiary meadow at Dixter started with several advantages. The soil was poor and it was an old-established lawn. Christopher adopted the regime he used for the rest of the Dixter meadows: a first cut in September and a last cut in February. This enables the spring flowers to display themselves against quite a tight turf, but also allows time for the summer flowers and grasses to seed themselves about.

In his Gloucestershire garden, John Sales, who for nearly 30 years was Head of Gardens at the National Trust, gave himself a meadow by taking in part of the neighbouring field. A close-mown path divides the area into two, one half managed roughly on the Dixter mowing regime, the other half mown until mid-May before the grass is allowed to grow long. This keeps it looking tidier through the second half of summer and encourages a slightly different cast of characters. Although it has obvious advantages that regime wouldn't suit Foxpatch. The orchids that grow there are the southern marsh type (Dactylorhiza praetermissa); we'd be mowing them down just as they were coming into full growth.

But what do you do if you want a "meadow", but don't have the kind of lawn you can just allow to grow into one? Purists say you must strip the existing turf together with some of the topsoil and seed the less fertile earth underneath. If you can marshal an army of slaves to help, that might be possible, because in a typical garden setting all that labour will have to be done by hand.

Then you need to choose a seed mixture which most closely matches your conditions (and your dreams): clay soil, dry soil, acid soil, chalk soil, spring flowering, summer flowering, hedgerow, water's edge. Mixes are made up to suit a wide variety of possibilities. Is this what I'd do? No. If I was meadow-gardening on a small scale, I'd work with what grass I'd got and plug in plants such as meadow cranesbill, cowslips, monkshood, camassia. Purists may sneer, and the end result may not be a true meadow. But the bees would be just as happy. And you will have saved yourself a lot of hard labour.

For tailored seed mixtures of wildflowers, go to Emorsgate Seeds, Limes Farm, Tilney All Saints, King's Lynn, Norfolk PE34 4RT, tel: 01553 829028, email: enquiries@emorsgateseeds.com; wildseed.co.uk