Lynne Truss on a grass-roots show that separates the gardeners from those who trifle with peat

On a fine spring morning of birdsong and sparkling dew, we are just wondering what we have let ourselves in for, here at Ham House near Richmond, Surrey, when an unremarked piece of topiary, shaped not much like a chicken, suddenly speaks out. “Over here,” it says, its beak section (or thereabouts) hinging open and shut while its audience recovers nervously from the surprise. “What’s the matter? Never heard a talking bush? My ancestors go back to the Hanging Gardens of Babylon, you know. But the 17th century, when this house was built! Oh, those were the days for a topiaryI” Mud, Mulch and Marigolds will be touring National Trust properties this summer, playing to NT visitors at the weekends and school parties during the week. And after last week’s entertaining run-through at Ham House, the only fear is that the talking topiary is toogood: “sculpted bushes: their part in rhetoric” might become a regular research topic among secondary-school students.

The central idea of M, M and M is a television shoot. A quick-fix television gardener called Mary Gold (Lisa O’Hanlon) has commandeered the garden. A diminutive prima donna in gaudy yellows who shrieks, “What on Arth is this supposed to be?”, she bullies us into waving outsize marigolds and singing her theme song, “Let it be told, Mary, Mary Gold, How do you make your perfect garden grow?” Does Mary Gold turn out to be a charlatan who knows nothing about gardening and cares less? You bet. First, she is sponsored by a peat company (no!). The fact that she is first discovered trimming the topiary with a fork and trowel is another pretty good clue.

Meanwhile, the garden is populated by other characters who highlight issues such as the irresponsible use of peat (no!). A pair of kids with worksheets and loosened school ties have a charming scene discussing every individual’s responsibility to save the environment - but thankfully with something personal transpiring between them. Throughout the hour of the show, self-styled “plant hunters” (furtive cads in raincoats) roam the garden, nicking cuttings in slapstick manner. A woman whose dog has died wants to erect a monument to it.

And finally, a loud, odd and imperious woman in an Edwardian skirt turns out to be the great English garden designer Gertrude Jekyll (1843-1932), and not a deranged person, which is a relief. Ms Jekyll hands us potted herbs to sniff and tries to enthuse us about herbaceous borders involving lupins. She tells us that the wife of Edwin Lutyens, the Victorian architect with whom she so often collaborated, always referred to Ms Jkyll as “Bumps”. No love lost there, then. Whatever key stage 3 and 4 pupils already know about gardening issues, they are likely to be entertained by such a dynamic presentation.

Meanwhile, the accompanying resource pack, which arrives in a flowerpot, sets an ingenious range of tasks, the best of which is the Great Estates Trading Game. Competitors must imagine themselves the incumbents of large estates in 1900, to be managed right through to the year 2000, with tokens for cash, tokens for gardeners, and so on. It is inventively done. Wars intervene. The gardeners go off to be killed in trenches. Land girls arrive. Machinery starts to take the place of labour. I learned many wide-ranging gardening facts from the education pack, which is aimed at such curriculum areas as geography, art and design and citizenship.

For example, Barrington Court in Somerset has a kitchen garden (founded in the 1920s) with 104 varieties of fruit tree. TV gardener and Ground Force presenter Alan Titchmarsh supposedly inspired the creation of comedian Steve Coogan’s alter-ego, Alan Partridge (from his now-forgotten days as a celebrity interviewer on the BBC’s Pebble Mill at One). The nemotode is a parasite that penetrates a slug’s body and eats it alive. In Victorian times, marigolds were symbolic of despair. The use of peat in gardening (no!) is a bad, indeed, a very shockingly bad thing.

Back at Great Estates, we reach 1965, when it gets a bit too realistic. Swingeing death duties force you to make big decisions: do you stage a pop festival (poisoned chalice), open a safari park (smelly), or hand the whole caboodle over to the National Trust (which solves all your problems at a stroke, but charges you for your own veg)?

I particularly liked the choice presented in 1995, when the BBC asks to use your grounds for the filming of its costume drama, Sprig Muslin and Scarlet Regimentals (great title). Competitors must answer a simple costume-drama question to acquire this boon, naming an actor with smouldering eyes, attractive ginger sideburns and a big, wet, flappy shirt. Well, there were high-fives in this house. But what if Mr Darcy endorsed the use of peat (no!) at Pemberley? The sturdy moral structure of Jane Austen’s universe is blown to bits in an instant.

Lynne Truss is a writer, critic and broadcaster. Her novel about gardening, With One Lousy Free Packet of Seed, is published by Penguin.School performances of Mud, Mulch and Marigolds and teachers’ briefings take place at various National Trust venues until late September. Next: Castle Ward, Northern Ireland (May 16-18) and Washington Old Hall, Tyne amp; Wear (June 13-15). Shows at10am and 2pm daily. More details and all bookings on 020 8986 0123