One of the puzzling things about the recession we find ourselves in at the moment is that many specialist nurseries are actually doing better than they normally would. So when I visited Special Plants, at Cold Ashton, near Bath, a couple of weeks ago I found the staff attempting to eat their lunches in mid-afternoon. Their entire morning had been taken up with selling plants and finally hunger had overtaken them – even though customers like me were still prowling the territory.

This is a great nursery, which was started by an American called Derry Watkins in about 1996. It’s located in a steep valley with unspoilt views, and if you’ve ever negotiated Bob Brown’s bumpy lane down to Cotswold Garden Flowers, at Badsey, near Evesham, you’ll understand when I explain that Derry’s drive is a much narrower and even longer. It’s not for the nervous and you definitely wouldn’t chance up on it by accident.

But it’s worth the expedition, because Special Plants is full of unusual treasures – both hardy and tender. Many have almost-black flowers or foliage because Derry only grows the plants she is passionate about and she grows them extremely cleverly. They romp away in the garden setting.

Many of them have a wiry, structural quality which makes them good performers in the modern garden. In fact, Derry’s plants emulate her energy and enthusiasm perfectly. Derry also has a seed catalogue from seeds collected from her nursery and garden. You can access the list at www.special-plants.net/seeds or telephone 01225 891686.

There are many umbellifers, lots of annuals and biennials plus perennials. Star plants include the man-high lanky, perennial coneflower Ratibida pinnata. Its drooping yellow petals frame a brown-green cone from August onwards. A tender, perennial umbellifer with dark leaves and flowers called Trachelium ‘Black Knight’ and the tactile mouse-eared purple annual called Cuphea viscossima are two more unusual finds. But there are many.

I also admired her meadow plantings of bright annuals grown from seeds supplied by Pictorial Meadows. Forget tasteful natives. These mixtures include a Volcanic Annual Mixture of red clover, purple cornflower, red orache and red flax. The Candy Annual Mix is dazzlingly ethereal with delicate poppies, fairy toadflax and tickseed. These are just two of the many mixtures available in 50g packs designed to cover six square metres. They cost an average of £15 and you do need to plant them in tracts or swathes so that they work visually.

At the moment I am enjoying a billowing mixture of blue cornflowers (Centaurea cyanus) planted with a white cosmos called ‘Psyche White’. These are jostling alongside an annual white lace flower called Ammi majus.

The 12ft strip is about a metre wide and it is pulling in bumble bees and hoverflies all the time. Both creatures are vital in gardens.

Bumble bees are excellent pollinators and hoverflies have predatory larvae that eat aphids and other small pests.

The blue cornflower is adored by red-tailed bumble bees and they seem to prefer it to all other flowers.