Now that deciduous trees have lost their leaves the colonies of mistletoe Viscum album that have been spreading across the country are more obvious. A species that was rare outside the south-east Midlands is now quite common in many areas where it is seen growing mostly on apple, lime, poplar and hawthorn trees.
The Victorian demand for mistletoe was once so great that the British crop from apple orchards was insufficient and hundreds of tonnes had to be imported from France. Every home had to have a sprig at Christmas as an excuse for a clandestine kiss.
Mistletoe is a slow-growing plant and easily controlled but because it is a parasite, drawing its nutrients and water from its host tree, it can do serious damage. Only the female plants have the white berries so the uncut male plants can grow enormous if left alone.
There is much debate among scientists about the reasons for the advance of mistletoe. The favourite theory is that the blackcap or Sylvia atricapilla is responsible. It is a bird that used to migrate further south but now overwinters in Britain. It eats the white berries and but not the seeds, wiping its beak on nearby bark, effectively planting the sticky seed on a new host tree. The warmer winters also suit mistletoe.
