Last updated: 07 April 2008
Bluebells rate highly on 'favourite British flower' surveys, which is quite appropriate as Britain contains half the world's population.
About 70% are found in woodland, but much of this ideal habitat has been destroyed for agriculture or converted to coniferous woodland.
They can grow and sow seeds before the trees produce leaves, reducing space and light. However, temperatures are getting warmer, bringing spring forward by six days for every degree celsius. In other words, this 'head start' is getting smaller.
The Spanish bluebells were introduced to British gardens in the 17th century, but it wasn't until the 20th century that they escaped into the wild. As a result, a third of bluebells are either a Spanish or hybrid variety, and one in six bluebell woods contains a mixture of all three species.
Bluebells are not restricted to woodlands. The further west in Britain you go, the more widespread bluebells become in other habitats such as grassland, heath, scrub, sea cliffs and hedge-banks.
They can even be found adorning mountain sides, with the highest recorded bluebells reaching up to 685m on Craig-yr-Ysfa in Snowdonia.
Try one of the walks from Derek's latest walking series on BBC One Wales.
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