Grow by numbers

THE SUNFLOWER, or helianthus, has been grown in Britain for four centuries, but it spent a long time out of favour. For years it was looked upon as something of a joke flower, climbing to a ridiculous height and bearing a top-heavy head that soon sagged and withered away.

Some grew them for their edible seeds, while schoolchildren, intrigued by their size, strove to rival the world record of about seven metres. Not even the labours of Vincent van Gogh could transform the sunflower's unfashionable image.

But in the past two or three years, all this has changed. Vases of sunflowers lurk in the corners of smart bistros, ballrooms and boutiques. They creep into the background of glossy advertisements for fast cars and high fashion. Seed merchants and florists report unprecedented demand for them for gardens and ambitious indoor arrangements.

Marks & Spencer, barometer of popular taste, began selling them as cut flowers two years ago and now offer them all year round. They have become one of the chain's strongest floral lines and were prominent on its large stand at the Hampton Court Flower Show this summer. Seed merchants, not much slower to spot a trend, are introducing new varieties of sunflower whose appeal is not based on gigantism but on their suitability as cut flowers for display in vases.

The scientific breakthrough that allowed the sunflower to be house-trained was the development a few years ago of a virtually pollen-free breed. These new varieties do not shed the irritating black dust that gets in your carpet, on your clothes, and up your nose.

The other critical factor was a shift in style. "In the 1980s people only wanted cut flowers in soft, co-ordinating shades," notes Nick Herbert of M&S. "But the last few years has seen a trend towards bright, strong and vivid colours. That is what made us think of sunflowers."

Their dazzling yellow petals certainly merit all three of those adjectives. The British grower for M&S is David Needham, who has a large nursery near King's Lynn in Norfolk. This summer, for the first time, he covered 10 acres with swaying black and yellow flower-heads of the uniform size and conformity M & S demands. Between late July and late September, he has been sending out an average of 8,000 blooms a day.

Needham, who grows several other flowers under glass for M&S, was asked five years ago to try sunflowers by Cherry Harpen, whose packaging and distribution company, Flowerplus, in nearby Spalding, supplies M&S with many of its cut flowers. Her demands were formidable. She wanted blooms that were pollen-free, about 15cm in diameter, on 70cm stems. They had to have unusually short petals, to cut the risk of damage on the journey from nursery to customer's living-room vase. Life expectancy had to be about two weeks, and they had to be tough enough to survive without water for a few hours.

In other words, Needham was being asked to apply, to the uncertain business of horticulture, the kind of strict quality control that ensures each pair of St Michael trousers and packet of chicken chasseur reaches a consistent standard. He began experimenting. With Cherry Harpen's help, he settled on the most suitable new variety, called "Sunbright". Now the challenge was to devise growing conditions that would allow the M&S specifications to be met.

In his first full year of trials, most of Needham's sunflowers were too tall and some of the heads measured 30cm - twice the diameter wanted. By year three, only about a fifth of the crop met the criteria.

Just as if you plant vegetables close together you will get a smaller yield per plant, the way to stop flowers getting too big is to crowd them, making them compete for nutrition. As a result of four years of experiment, Needham now sows the seeds a mere 5cm apart. He reckons that this year 70 per cent of the flowers meet the standard, and he is confident that next year he will get that up to 80 per cent.

He plants the seeds direct into the ground over two months from the beginning of April. The flowers should mature between mid-July and late September, but this year's hot summer has meant that the later-planted ones are maturing early and cropping may end prematurely.

In his fertile fenland soil, the flowers need little nourishment except an occasional dose of a standard potato fertiliser. They are prone to aphid attacks in early summer, but a single spraying of insecticide in May usually clears the problem. They are watered at their vulnerable germination period but not after that - not even in this long hot summer.

The flowers are picked in the early morning and reach Flowerplus before noon. There they are made up into bunches of three (current price pounds 3.99) or added to other flowers in ready-made bouquets. They are sent to the M&S warehouses in the afternoon and are in the shops the following morning.

Not all of the sunflowers rejected by M&S go to waste. Many are of good enough quality for Needham to send them to other customers or to wholesale markets. The rest are thrown away or ploughed back into the soil. Needham, who was primarily a tomato grower until the end of the 1980s, does not mind working for such a rigorous client as Harpen. "It's a crop that I like, because it's something I've developed. It's great for me, because every year or two these people come to me and say, 'Can you grow something else for us?' "

It is hard to say where fads in horticulture originate. If flower sellers have half an eye on what people are doing in their gardens, seed merchants keep up with trends in cut flowers - reasoning that if people buy blooms for the house they may want to grow them for themselves When Unwins showed the new varieties in next season's catalogue last month there was much interest in a pollen-free sunflower seed packaged as "Oranges and Lemons". It is a mixture of two varieties - one bright yellow, the other with a distinct orange tint, growing to about 90cm. "We think there's a big demand for them as cut flowers," says Amanda Sanders, Unwins' technical manager.

Cherry Harpen, keen to stay ahead of the game, is trying to guess how long sunflowers will stay in vogue, and what will supersede them. Because a new flower can take five years to develop for sale, it is important to guess right.

"The cottage garden look is in now," she says. "Antirrhinums are back, and delphiniums and peonies. We're trying to get into our shops the cut- flower version of the English country garden." !