May is the month for observing broad swathes of bluebells carpeting old woodlands and running along the edges of old hedgerows. They emit a sweet scent and are pollinated by insects, especially bumblebees.
The native Bluebell (Hyacinthoides non-scripta) has bell-shaped flowers on one side of a drooping stem. The flowers are a deep blue tending towards purple and each one is curved backwards at the top. The leaves are narrow.
This bluebell, however, can be confused with the Spanish bluebell (Hyacinthoides hispanica) which was introduced to the country in the 19th century. This bluebell originates in Spain, Portugal and North Africa and can cross-pollinate with the native one creating another bluebell called a Hybrid bluebell (Hyacinthoides x massartiana)
On close observation of the Spanish bluebell, however, clear differences can be seen between it and the native one. This introduced species has much larger leaves and larger flowers which are attached all around the erect stem instead of one side only. The flowers have very little scent and are a pale blue instead of deep blue. The tips do not curl inwards but are splayed outwards.
Spanish bluebells are mostly found in gardens but if these gardens are near old woodland or hedgerows that have the native bluebells cross pollination can occur. This hybridisation can greatly affect the integrity of the woodland or hedgerow.