Bluebell blues as most popular wildflower feels the squeeze

It has been the inspiration of poets. But, as climate change transforms the British countryside, our most popular wild flower is finding itself crowded out by other plants. Jonathan Brown reports

Writing from the "edge of his private hell", the poet Gerard Manley Hopkins saw in the humble bluebell the very "glory of God". "The blue buzzed-haze and the wafts of intoxicant perfume" of Hyacinthoides non-scripta which so enraptured Hopkins in his state of theology-induced melancholy, exert a similarly powerful effect over the rest of Britain.

Writing from the "edge of his private hell", the poet Gerard Manley Hopkins saw in the humble bluebell the very "glory of God". "The blue buzzed-haze and the wafts of intoxicant perfume" of Hyacinthoides non-scripta which so enraptured Hopkins in his state of theology-induced melancholy, exert a similarly powerful effect over the rest of Britain.

In the next two weeks, hundreds of thousands of nature lovers, from Scotland to Surrey will journey into the woods to enjoy Britain's most spectacular wild flower display. Thousands more will come from overseas to take part in hundreds of bluebell walks. In Oxfordshire, Worcestershire and Sussex, special trains will deliver devotees of the bluebell to woodland sites. There will even be a bluebell church service at Swithland Wood in Leicestershire

But the future of this natural marvel is under threat on all fronts. Officially a declining species, the most recent and potentially devastating challenge is from global warming. Climate change has already begun to unleash subtle changes on the British countryside. Last week the UK Phenology Network reported that spring was getting earlier. January was two degrees warmer than the long-term average, and winter resulted in a record number of unseasonal events. From the flowering of daffodils in December to frogspawn in October, nature's alarm clock is going off early. It is estimated that for every one-degree Celsius rise, spring advances by six days.

This creates particular problems for the bluebell, which takes advantage of a brief window of opportunity in nature - the time between the warming of the soil and the closure of the woodland canopy. Seventy per cent of bluebells are found in woodland and broadleaf forests. With spring recorded earlier each year, the canopy is coming earlier, so this window is slowly closing. The bluebell could be losing its competitive advantage as other plants bring their rapid growth period forward. Unless the bluebell reaches maturation before the other plants, it cannot set viable seed and ensure a fresh carpeting of flowers the following spring.

The British Isles is the home of the bluebell. It is not only the most popular - it is regularly voted Britain's favourite flower - but our forests, meadows and cliff tops play host to half the world's population. They are only found in significant numbers in the similarly changeable Atlantic climates of northern France and the north of Spain.

The first bluebell shoots emerge in January, when the branches of the leaves are bare. This early flowering habit allows the plant to tolerate the extreme shade of the woods and contend with the smothering effects of rivals such as bracken and Japanese knotweed.

They eventually flower in April and May when for just two or three weeks they carpet the woodland floor.

Simon Cole has managed 40 acres of bluebell woods at the Royal Botanical Gardens, in Kew, west London, for three years. He is bracing himself for one of the busiest weekends of the year as nearly 50,000 people descend on Kew for the Mayday Woodland Festival, timed to coincide with the flowering of the bluebells.

The appeal is obvious, he said. "This is the emblematic plant of this country and has been voted the most popular. It not only puts on a fabulous display but it is in a very unusual colour. Blue rarely occurs in nature," he said.

But it was not always so. Before Hopkins saw salvation in the swaying stems, many feared them. Forests were considered to be enchanted rather than enchanting. A popular folk tale was that the flowers' bell heads summoned summer fairies to woodland gatherings. A human who heard one chime faced imminent and inevitable death. To bring a bunch into the house was considered bad luck.

But as they grew in the nation's affections, they have become increasingly threatened. Perhaps the most serious danger can be traced back to 1680 when the first Spanish bluebells were planted in British gardens. For more than 200 years, Hyacinthoides hispanica was safely contained. But in 1909 it escaped into the wild and since then it has been on the march. The Iberian interloper, more upright and lighter in colour, bred readily with the native bluebell producing a scentless hybrid Hyancinthoides X-non scripta. This too bred with the indigenous plant. One in three plants is now an interloper or one of its offspring, while one in six bluebell woods is diluted by cross breeding.

The advance of natural competition coincided with the catastrophic loss of the bluebell's habitat. By 2000, just 5 per cent of Britain was covered in trees, making it the least wooded country in Europe.

And if these threats were not enough, man is menacing the plant in an even more direct way. The uprooting of native bluebells for sale in garden centres has posed a problem since the Second World War. In 1998, the bluebell finally fell under the protective wing of Schedule 8 of the Wildlife and Countryside Act 1981, which made it illegal to collect them in the wild.

Meanwhile at Kew, Simon Cole is fighting yet another threat to the native bluebell population, the Smyrnium, a type of wild celery, native to southern Europe, south-west Asia and north Africa.

Considerably taller and flowering at the same time as the bluebell, it is producing a new and unwelcome canopy of vegetation which chokes off the bluebell's light source.

The loss of the bluebell would have many obvious ramifications. It is a valuable source of nectar for spring insects and its disappearance could further undermine the already changing natural timetable. But it is the loss of visual and emotional punch of seeing a carpet of bluebells after a long winter that could have the greater long-term consequences. "Many people take great joy in witnessing what is one of spring's greatest spectacles," said Mr Cole. If it were to disappear, we would lose yet another inspirational natural experience.

Under threat

Beech woods

Bisham Woods in Berkshire is among many in the South-east threatened by water shortages and drought brought on by drier winter and summer conditions.

Spotted flycatcher

Reduction of invertebrates outside Europe blamed for 85 per cent decline in numbers of this woodland bird in Britain. Massive drop in first-year survival rates.

Snowdon Lily

Rare and beautiful Arctic upland flower that is found on increasingly higher ground in Snowdonia, North Wales. This is the only place in Britain where it can be found.

Asian longhorn beetle

Warmer weather conditions favours the beetle, a devastating pest for hardwood trees that can be killed only by removing and destroying affected trees.

Mountain ringlet butterfly

A sensitive indicator of change. Northern butterflies continue to seek temporary sanctuary on cooler higher ground.