Herb your enthusiasm: Meet the expert herbalist who knows exactly what thyme it is

Jekka McVicar is a bit of a legend: admirers talk of her 60 RHS gold medals; of the day Heston Blumenthal nibbled half of her stock in one visit; how she serves her staff their morning coffee with home-made meringues flavoured with her own mint and caraway seed...

McVicar has grown herbs organically for 25 years – and she isn't tired of them yet. "There's always something new," she says. "The world's getting smaller and we are finding new plants all the time." It's the depth of her knowledge and passion for the subject that has persuaded chefs such as Jamie Oliver and Blumenthal to make their way to her West Country HQ and wander through her collection.

McVicar's passion for herbs started early. "I was a mum," she says, "and I had two tiny children crawling round my feet. So I thought, 'How do you give them freedom, but protect them at the same time?' To me, the idea of growing stuff organically was obvious."

Today, her expertise is crammed into her books, the most famous of which is just being reissued in paperback: Jekka's Complete Herb Book (Kyle Cathie, £16.99). Half a million people in Britain own a copy, referring to it whenever they need to remind themselves of the 38 different kinds of thyme they could be growing.

McVicar also still runs her farm, in a gorgeous spot of countryside just a few miles from Bristol. The herb farm closes all winter while the staff tidy up and prepare for another season. Right now, they are gearing up for the first of their 2009 open days. It's a real family affair: McVicar's husband Mac organises the car park, while the gorgeous floral catalogue is designed by their daughter. McVicar herself delivers her talks standing on a footstool. They have proved so popular that this year, for the first time, they will be bookable: the last weekend of March, McVicar will do a seed-sowing workshop and a talk on "Medicinal Herbs in the Home".

And she has plenty more to look forward to: this year McVicar takes over the prestigious marquee area at Chelsea that's always been known as the "Notcutts stand", which will become a world stage for McVicar's continuing crusade for herbs. She just needs to make sure she wards off any more marauding chefs.

"Heston was dangerous," she chuckles. "He was like a child in a sweetie shop. He was stuffing everything into his mouth. And herbs – they are the basis of our medicine. You have to be respectful of their strength. Oh well," she sighs, "he didn't die, I'm very pleased to say."

Pick of the bunch: Jekka's window-box recommendations

Chives

"Because they behave well."

Allium schoenoprasum, £3.50 a pot

Rosemary

"I'd have a prostrate one that would hang over the side of the window box."

Capri rosemary, £4

Thyme

"Go for something like Porlock, with a bit more leaf than the species."

£4 a pot

Mint

"Plant it in a separate pot, because it'll spread like mad. I'd have apple mint because it works for mint sauce and mint tea as well as being fantasticwith fruit or yoghurt."

Mentha suaveolens, £3.50 a pot

All from www.jekkasherbfarm.com