Bluebells grow best in undisturbed soil where trees cut out the sunlight in summer, preventing other plants from taking over. The ancient woodland often seen in southern Britain is perfect for bluebells and at the right time of year you will almost certainly see masses of gently arching violet-blue bells along the footpaths.
The sensitivity of bluebells to the right conditions make them an excellent indicator of ancient woodland (woods that have existed continuously without clearing and replanting since 1600) and some of the bluebell populations you will see are hundreds of years old.
Bluebells grow from bulbs buried deep underground (up to 5 inches) where there is more moisture than at the surface. Their journey to this depth begins after the germination of seed on the surface. The small bulb that develops has special roots that contract and pull the bulb deeper into the soil.
Mature bluebells begin to grow as winter begins to lose its grip but the rate of growth depends on weather conditions. After a severe or extended cold spell flowering can be delayed by several days. Usually shoots can be seen emerging from the soil in February and by late April the sweetly scented flowers start to open. Now the flowers are the centre of attention for butterflies, bumblebees and other insects interested in the rich bluebell nectar.
By the end of May the spectacle is over. Now each plant concentrates on developing small black seeds that are housed in pods attached to the once-nodding bluebell stalk. In the photograph you can see seeds in three chambers in the seed pod, each at differing stages of ripeness. By the end of June the tree canopy has cut out most of the light at ground level and the seed pods have opened, scattering seeds on the ground.
It is thought that Britain has approximately half the world’s population of bluebells. The native bluebells that grow in British woods are also found in the wild along the western edge of Europe (Ireland, France, Belgium, Netherlands, Spain and Portugal) but these populations are sparser and more unevenly distributed than those in the British Isles.
There are other areas of bluebells in Germany, Italy, Romania and North America but these have resulted from introduction by man.
Types of Bluebell
Until the 1860s the only bluebells in British woodlands were the native variety, also known as the English or Common Bluebell. Around this time Spanish Bluebells were introduced to British gardens as an ornamental plant. The Spanish Bluebell was favoured because it could grow anywhere and had larger blooms. Naturally the Spanish Bluebell eventually escaped from our gardens and the first record of a Spanish Bluebell in the wild was in 1909.
It is thought that English and Spanish Bluebells probably evolved in isolation from a common ancestor in Europe about 8000 years ago. However, as they are genetically similar, the two species hybridise readily and produce plants that have a mixture of the traits of their parents.
This potentially presents a problem for our native woodland stock as pollen can travel over large distances. The first record of a hybrid bluebell in the wild was in 1963 and now hybrid bluebells are commonly found in hedgerows, roadsides and waste ground. Despite this, recent research shows that the English bluebell is more fertile than its Spanish cousin. This means that natural selection will always favour the English variety. If this is true then a woodland with mixed bluebells will always revert to the English variety.
Flowers of the English Bluebell are tube-like bells suspended from a graceful arch which stoops in one direction under the weight of the bells. By contrast Spanish Bluebells have an upright flower stem with flowers emerging from the stem in all directions. English Bluebells also have a strong sweet scent and pale cream pollen whereas Spanish Bluebells have dark blue pollen but no scent. Both plants produce up to 8 linear leaves growing from the base. English Bluebells have narrow leaves about 10mm wide whilst the Spanish variety has leaves twice as wide.
As would be expected, the hybrid between English and Spanish Bluebells shows a mixture of these traits, giving a slightly scented bluebell with pale blue flowers on a stem that curves slightly. The pollen of the hybrid is pale blue.
Wild Hyacinth (Scotland)
Bluebells in the Garden
Bluebells are best seen en-mass in their natural setting but many people wish to have them as a garden plant. Bluebells can be planted as dry bulbs or in a condition known as ‘in-the-green’. In-the-green bulbs are dug up by plant specialists in early spring when the bulbs are actively growing. They are then carefully wrapped to preserve moisture and dispatched, ready for immediate planting on arrival.
Planting bluebells ‘in-the-green’ is a more reliable way of quickly establishing a population of bluebells as dry bulbs can often remain dormant for 3 years or more after planting. There are many stockists of English Bluebell bulbs available on line and some garden centres now sell English Bluebells in pots during the spring. If you live in the UK please be aware that it is against the law to dig up bluebells growing in the wild.
Bluebells growing habits can make them difficult to remove. As the bulbs are deeply buried and reproduce by creating smaller offset bulbs, once established several attempts may be necessary to prevent them from re-appearing. Bluebells are strongly resistant to weed killers and the Spanish variety is more invasive due to its more vigorous nature.
If you do wish to dig your bluebells up do not dispose of them by adding fresh to your compost as they will readily grow again. Ensure they are killed first by placing in a black sack and leaving for a year or more before adding to the compost. Alternatively dig plants up after they have flowered and, with their leaves intact, leave them in the sun to dry out for more than a month. Never dispose of unwanted bulbs in the countryside.
Bluebells and Climate Change
The date that bluebells first begin to flower varies depending on weather conditions but the long term effect of climate change on bluebells and their habitat is not yet known. One study recently showed that the average flowering season appears to be two weeks earlier than it was 30 years ago. The Natural History Museum in London ask the public to record their sightings of the first bluebell each year. These are added to the accumulating body of evidence about climate change.
As part of a campaign to save plant life from climate change and other pressures worldwide, the Millenium Seed Bank was set up at Wakehurst Place. Only a short distance from the Bluebell Railway, the seed bank is open to the public.
The vulnerability of English Bluebells has led to their protected status and the Wildlife and Countryside Act 1981 makes it a criminal offence to remove the bulbs of wild English Bluebells.
Only two percent of Britain remains as ancient woodland today so the preservation of this rich habitat for wildlife (and bluebells) is vitally important. A number of groups including the Woodland Trust are working to promote the protection of British woodland and forests.
Bluebells and The Bluebell Railway
The Bluebell Railway is very aptly named. At the right time of year you will see carpets of bluebells as you steam from one end of the line to the other. You will also see bluebells up-close on all of the walks on this website, except for the “East Grinstead” walk where tree cover and undisturbed soil (the conditions under which bluebells thrive) are far more limited because of its sub-urban nature.
Best Time to See Bluebells
In Britain and other parts of the Northern hemisphere the best time to see bluebells is between the end of April and the beginning of May.
Good timing is essential when trying to catch bluebells at their peak. They tend to be best at the end of the flowering season in April/May but only a week separates stunning carpets of blue from the fading green of setting seeds.
The video shows what you might see during the bluebell flowering season and the graph shows how bluebell quality (flower density) varies with time. 2020 saw a milder winter than 2016 and a very warm and sunny spring. The bluebells flowered about one week earlier than usual in 2020.
Whilst you will see a few bluebells in the first two weeks in April you are far more likely to get a good show in the second half of the month. Bluebell quality rapidly declines after the first week in May and within the space of a week the bluebells suddenly disappear.
The timelapse was taken in Ashplats Wood, East Grinstead, West Sussex, UK during 2016. This followed a typically mild winter in the south of England. Bluebells flower slightly later after a cold winter or at latitudes further north.
In Australia, New Zealand and other parts of the Southern hemisphere the best time to see bluebells is between the end of October and the beginning of November.