Sharon Giffiths meets... national plant collection gardener Dianne Nichol-Brown.

JUST before her garden is about to open to the public, Dianne Nichol-Brown is sitting outside in the sunshine, a big bowl on her lap, happily mixing up the scones to serve to her visitors.

"So much nicer when they're freshly made and warm from the oven," she says, at the same time as explaining some of the unusual plants in her garden, many of them from hot and dry climates, yet flourishing happily under her care in Trimdon, where the wind blows straight off the North Sea.

Don't be fooled. Dianne may give the impression of being utterly relaxed and laid back, but that's probably only because she is fiendishly well organised.

In the famous Yellow Book of the National Garden Society gardens which are open to the public, hers stands out a bit. In among the halls and granges and big houses, you don't expect to see 28 Sunnyside Terrace, Trimdon Grange. But this tiny garden is home to four national plant collections, principally of polemoniaceae - Jacob's ladder and related plants - and was awarded scientific status in 1999. It houses more than 70 species and Dianne is regularly asked to cultivate new varieties.

Then there's collomias, gilias, leptodactylons...

Collecting plants takes Dianne and her husband David all over the world.

"We travel round looking for plants and they always seem to be in inaccessible places, up mountains or across the other side of raging torrential rivers. We've been 14,000ft up in the Rocky Mountains, then down on the hot dry plains, miles from anywhere. One of our selections is called gold mine, because we found the plants on the side of a road to an old mine."

Originally, the collection grew in an even smaller garden in Ebchester, but when David and Dianne married seven years ago, they moved to Trimdon and the entire collection - trees, shrubs, plants - moved too. The Trimdon garden was, at the time, virtually all concrete, but five months and a lot of work later, the Nichol-Browns were opening their new garden to the public.

"I've always been a gardener and an organic one too. My granddad had an allotment and being a good Yorkshireman, never believed in buying pesticides," says Dianne, who has a first class degree in plant biology.

"To me it seemed logical," she says of this. "I loved plants and wanted to know everything about them. You wouldn't expect a doctor not to know physiology so it's the same for gardeners."

When she became interested in polemoniums, she discovered that many of them were incorrectly named, even by top nurseries and seed suppliers. So she wrote the only complete reference book on them too.

She lectures on ecology and conservation at Houghall College, Durham - where there are 400 acres. "So having a small garden is enough for me. I've got enough acres at work. This is my relaxation where I can do just as I want," says Dianne.

We are sitting in the Secret Garden, a small sun trap filled with rare and unusual plants, including an enormous New Zealand bush and lots of flowers with black leaves or foliage. Among the first visitors were students from Dianne's course on organic gardening. "They need to see that I practise what I preach," she says.

Among her chemical-free ways of getting rid of slugs, for instance, is to scatter chilli pepper around the plants. "They don't like that," says Dianne.

Many people who open their gardens to the public spend the weeks and days before in agony lest flowers aren't at their best at the right time. Not Dianne. "We don't do big and blowsy flowers. It's not that sort of garden, but there's always something of interest to look at whatever time of year you come. "

They open on just two bank holidays a year, May and August. Not because that suits the plants, but because it suits Dianne. "I'm often working at weekends, but bank holidays are the one time I'm guaranteed to be free to be here."

As well as full time lecturing, talks and demonstrations, the Nichol-Browns have a nursery - largely run by David - dealing in mail order sales of plants and seeds. And they also do bed and breakfast.

In everything they do, they try to be organic, including making all the delicious cakes on offer for visitors - and on an allotment which they have as well as the garden.

"I've always believed in working with nature, not battling against it.

"We were organic long before it was fashionable, in the days when people just thought we were weird and we had to trail over to Hexham to get organic flour. Now, of course, you can it everywhere. It's nice to know that the rest of the world is catching up," says Dianne.

They got very cross at a recent comment on Gardeners' World when Monty Don suggested it was very unusual for a national collection to be grown organically.

"We've always done that! And he also said it was rare for national collections to be grown haphazardly in gardens, instead of regimented in rows. Well, again, look at us."

They had a stand at the Gardeners' World Live show in Birmingham earlier this month and were planning to see Monty Don and set the record straight.

Naturally, Dianne spends a lot of time working in her garden. But not, she says, to excess.

"Maybe when I'm having my cup of tea first thing in the morning, I'll be out here pottering, pulling a few weeds. But people shouldn't worry or fidget with a garden. Life's too short.

"A garden is meant to relax you. It's there to be enjoyed. The best part of a garden is to be sitting out there in the sunshine with a book, otherwise what's it all for?"

* The Polemonium Plantery, 28 Sunnyside Terrace, Trimdon Grange will be open on August Bank Holiday Sunday and Monday as part of the National Gardens scheme. It is also open at other times by appointment, tel: (01429) 881529

The nursery sells a range of hardy plants from snowdrops to sorbus, via polemoniums and relatives, specialising in plants for shade. All plants are grown totally organically and in peat-free compost. Details and plant catalogue at www.polemonium.co.uk