The Threat to our Bluebell Woods
Many people are moved by the sight of a bluebell wood in spring. As April comes, we await the very English sight of the nodding heads and blue carpets of the woodland floor and the complex aroma of the bluebells.
Bluebells can be found growing along the Line and a glimpse of their spectacle can be seen from the footpaths along the edge of Knott wood.
(During the bluebell season in April and May only, the owners of the wood, Rothamsted Research, kindly allow the public access to a circular path through the wood via an entrance gate 100m up the path crossing the Nickey Line at the top end of Knott Wood. Those entering the wood should not pick or dig up the bluebells, stay on the path, and keep dogs and children under control, as failure to do so could jeopardise future access. Note authorised shooting takes place at other times of the year in the wood).
The English bluebell (Hyacinthoides non-scripta), common in our woodlands is different from the Spanish bluebell (Hyacinthoides hispanica) normally grown in our gardens. When the two species grow close together they will hybridise, the hybrids are vigorous and may outgrow the pure species. Gardens not far from bluebell woods are the situation that causes the problem. Worse still, the Nickey Line provides an effective corridor between the two.
Spanish bluebells have the following features:
- Broader leaves (10-30 mm wide) and generally fewer per bulb
- A flower spike that stands up straight and is not nodding over to one side
- Flowers that are broader bell shapes (i.e. The flowers splay open more)
- Tips to the petals that are not rolled back so tightly
- Anthers that are often blue (cream in the English bluebell)
- No scent (also true of many hybrids)
The hybrids obviously show some but not all of these features.
Spanish bluebells (left) and English bluebells (right)
Britain is home to half the world’s English bluebells, so looking after them is mainly our responsibility. If we let the hybrids colonise our woodland then the situation will change at an increasing rate, and our venerable woodland flora will be irreconcilably different, the hybrid looking less delicate and scentless.
Shrinking violets - well secretive anyway!
The end of April and the beginning of May also brings the violet season. A chill winter followed by a prolonged spring, as happened in 2010, provides an extended period for the violets to flower. It is impossible to miss the common dog violet growing near Knott wood but keep looking; you may be able to find the sweet violet which is most easily distinguished by having the wonderful scent and also by its dark violet (not so blue) flowers, with spurs that are the colour of the flower. Later, when the flowering is apparently over, the violets flower again, but with secret (cleistogamous) flowers that never open. The male pollen fertilises the female directly and the petals never expand. The process obviously results in self fertilisation but still ensures seed for another year even if the genetic diversity is lower.