Mistletoe
Poisonous, mythical and parasitical
Another year has passed, and this will be my 41st Species of the Month – how time flies! So, as this is the month of Christmas, I thought I would do something obvious. No, it is not a robin, it is mistletoe.
Mistletoe is a familiar Christmas staple, soaked in folklore and midwinter tradition. But where does it grow and how can you find it in the wild?
What is mistletoe?
Mistletoe is an evergreen plant, of which there are more than 900 species around the world, with the only species native to the UK is the European mistletoe (Viscum album). It has distinctive forked branches and pairs of symmetrical evergreen leaves – which make it easier to spot in winter when all the leaves have fallen from other deciduous trees. In winter it produces clusters of snow-white berries, which are favourites of thrushes, blackbirds and fieldfares.
The plant is ‘hemiparasitic’, which means it takes some of its food from another plant. Mistletoe grows on the branches of trees, pulling water and nutrients from its host, while its green leaves also photosynthesise. Our mistletoe has the widest host range of all its relatives and grows in the branches of trees such as hawthorn, poplar and lime, although in the UK the most common hosts are cultivated apple trees.
Despite growing on trees, it is not generally found in woodlands, as it prefers its hosts in open situations with plenty of light. If you were looking to pick some mistletoe for Christmas, you are more likely to see it in gardens, orchards, parkland and even churchyards. This means that mistletoe would have been less abundant in ancient times when woodland was more widespread.
Where to find it
It’s commonly found in Wales, the West Midlands and the South of England, and is widely scattered elsewhere in England and Wales, but is rarely seen in eastern and northern England and Scotland. However, in recent years, mistletoe’s range in the UK has begun to expand, particularly into eastern areas of England. This may be due in part to an influx of continental blackcaps from Germany, which have started overwintering in Britain in the thousands. Blackcaps are migratory warblers that are becoming regular winter visitors to our bird tables, and feed on berries including those of mistletoe, which are an essential part of their winter diet.
The seeds inside are coated in a sticky substance that sticks to the beaks of birds feeding on the fruit. The birds then wipe their bills on twigs and branches, leaving behind the seed, or eat it and excrete it on trees in their droppings. The gluey pulp around the seed hardens and fastens the seed in place. As the new mistletoe plant grows, the roots penetrate the bark and start to take water and nutrients from the tree. It seems that blackcaps are more efficient at spreading mistletoe seeds than other birds, such as the mistle thrush, which also feed on the berries.
As with most things, you should always obtain the landowner’s permission before foraging for your Christmas garland, but it is also important not to take too much. This is because the mistletoe marble moth (Celypha woodiana), a priority species for conservation in the UK, needs this unusual plant to complete its life cycle. Its larvae overwinter in small mines chewed into the leaves of the plant, which become inflated by late spring when the larvae are fully grown. The larvae then emerge from the mines and pupate in a cocoon under bark or among lichens on the host tree. Sadly, this moth is only found in six English counties, and populations are declining due to over harvesting.
Mythology
As always, I like a bit of mythology and folklore, so here we go…
In Greek mythology, heroes were granted passage to the underworld with mistletoe. For Druidic societies, the plant was believed to give protection against evil and act as a cure for disease, and right through to the Middle Ages it had an association with fertility and vitality. Pagan societies thought it represented the divine male essence. In Norse mythology, Baldur’s mother Frigg declared mistletoe a symbol of love after her son’s resurrection.
Plus, who doesn’t like a kiss under the mistletoe at Christmas? Merry Christmas!
Megan Lock
Advisory
Photo credit: gailhampshire