In garden plants this year, black is the must-have color.
Plants with very dark foliage or very dark blooms are winning the popularity contest among fashionable gardeners.
Giant alliums are also "hot" this year, according to garden commentators' hype. But it may not just be hype. Neil Cummings, head plant buyer for one of Britain's leading garden-center chains, Dobbies, has noticed that giant alliums are "suddenly massively popular" after being just steady favorites for many years.
Another "in" plant this season in Britain is Crambe cordifolia (called giant kale in the US), a lovely summer explosion of tiny white flowerheads.
Bearded irises may (or may not, depending on whom you talk to) be staging a comeback.
Grasses are still doing well, and ferns, says Malcolm Berry, head of Britain's Wisley Garden Center, "are seeing a resurgence."
Since when did plants become "fashionable"?
The quick answer is, probably always. Gardening history - as you find if you read Penelope Hobhouse's recent book "The Story of Gardening" - is a narrative of changing tastes in plants. But this story took place over centuries.
Today, fashions are considered long-lived if they last two or three years. "People are not prepared to wait anymore," says Mr. Cummings.
"There is a tendency toward 'instant gardening' in our 'throwaway culture,' " agrees English Aquilegia (Columbine) specialist David Hitchcock. In his career as a nurseryman, which began in the 1950s, Mr. Hitchcock has had to adapt to changing plant fashions. He has had three specializations - dahlias, pinks, and now aquilegias.
Awareness of current trends and fashions must be an integral part of growing and marketing plants because, as garden center managers admit, they are catering more and more to "impulse buyers." Plants are often seen as expendable items in quickly changeable design schemes. "People tend to redecorate their garden," is the way Cummings describes it.
Some experts say, however, that it is still true that "plant trends tend to be reasonably long-lived. They have a longer life than high-street fashion, certainly," says Mr. Berry.
Who sets the fashions?
In Britain, a vast number of gardening and garden-makeover TV programs have the nation in their grip. Millions watch them, including nongardeners. The presenters are household names. This, above all, is what turns gardening on this small island into a fashion statement, agree experts here.
Carol Wallace, an American garden writer, observes, on the other hand, that in the US it is often gardening magazines that start fashions. "Nursery owners will tell you that when Horticulture or Fine Gardening features a plant, customers will soon be asking for it."
Ms. Wallace has herself written an article called "Is your garden a fashion victim?" and now she has been commissioned to write a book about "dark" plants. Laughing, she hopes that the fashion for them - which has already prompted a book published in Britain in 2000 - will last at least the next two years until her book comes out.
Wallace believes marketing is not what determines fashions. Rather, "when styles of gardening change, different plants start to be pushed. When cottage gardening gives way to native gardening, for example."
Hitchcock uses garden shows as display cases for his plants, and he believes strongly that specialist nurseries like his are the strongest trendsetters of all. Magazines or books can be helpful, but they follow rather than originate trends, he says.
He admits, however, that the media, particularly TV, can bring a plant a tremendous amount of publicity.
What's hot, what's not
Plants being in fashion also means other plants are out of fashion - though all plants do have their day in the sun.
"Fashions are cyclical," says Cummings.
Dahlias - out of fashion for decades - are still out of fashion in Britain. But there is the tiniest hint, here and there, of an upturn. Dahlia aficionados, such as Sarah Thomas of Winchester Growers Ltd in Cornwall, England, home of the English National Dahlia Collection (about 2000 varieties), are working hard to re-popularize this adaptable, multiform, wonderfully colorful, but overlooked plant.
Ms. Thomas says she never grew a dahlia in her home garden until she got involved in the national collection. "This year I'm growing around 300," she admits, showing how quickly a plant can "grow" on a gardener.
Hitchcock describes the ebbed interest in professional dahlia growing. "In the '50s, there were over 200 nurseries listed with the British Dahlia Growers Association. Now - four." Just the right time, he says, for an enthusiastic young person to go into it. "They could very quickly and easily, with some hard work, reproduce the popularity of the flower.".
Britain has long been a nation of enthusiastic gardeners. But today, gardening is an increasingly popular interest for younger people. According to a current catchphrase, "gardening is the new rock 'n' roll."
This youthful trend means that fashions - obvious or subtle - have a distinct impact. Some of the publicity for "black plants" this season has included doubtful comparison with the popularity of "the little black dress" - actually a long-lived fashion classic going strong since the 1930s.
It probably plays into the fashions for "Gothic" everything, and the universality of black clothes, particularly among young women. But whatever the promotional games, gardening experts agree that dark plants are becoming more popular.
Some older gardeners take a longer- term view of flower fashions. They admire the TV programs from a distance, and praise them because they are fostering interest in gardening for young people who have never thought of it before.
But they rather pooh-pooh the idea that they might be subject to such fashions.
Even if they acknowledge that everyone's tastes do naturally change over time, they suggest that the reasons for this are, at root, a mystery.
Ms. Hobhouse, long famous as a garden designer and a historian of gardens and plants, tells an amusingly self-effacing story along these lines.
"Six or seven years ago I went to Greece," she says in an interview. "Sitting underneath some olive trees in the Peloponnese having a picnic, I saw this wonderful annual growing which I had never seen in my life. By a miracle, I went back that autumn and got seed."
The plant, with strangely hooded flowers, turned out to be honeywort (Cerinthe major).
"Of course, it's been known about by botanists for centuries probably, back to Dioscorides," Hobhouse says, "but I had never seen it in a garden or in garden catalogs or even in lists of Victorian bedding plants."
In her own garden in Dorset, England, the plant took immediately. When visitors first saw it, they involuntarily oohed and aahed.
Then no more than a year later, Thompson and Morgan, a leading British seeds merchant, listed it. There was no way they could have obtained seed from Hobhouse. "It was pure coincidence," she says. "Just that extraordinary thing of people in different places suddenly realizing what a first-class plant it is, a really interesting plant. Nothing to do with me at all. And now it is commonplace in gardens."
So, sometimes, plants become popular just because ... they become popular.
"We may think we're above taste," says Hobhouse with a chuckle, "but of course we're not. We are part of our time."