Mistletoe is a plant with a rich history in folklore. By the18th century, it had become a feature of Christmas celebrations – the source of which appears to be unknown - but the tradition of stolen kisses under its white-berried arching leaves have continued ever since. Many of us will only be fleetingly aware of Mistletoe over the festive period so here’s an opportunity to find out a little more about the plant and where we might be able to see it this winter.
Mistletoe Viscum album is our only native, white-berried plant. Although it’s widespread in Europe, here we are at the northernmost limits of its range. It is hemi-parasitic, with green leaves capturing light and a network of slender projections from its root, known as haustorium, these serve to gather water and minerals from a host tree. These long-lived perennials go unnoticed when trees are in leaf during the summer and become more visible at this time of year.
Locally, Mistletoe has become easier to find in recent years. Populations have traditionally been static with clumps persisting in a particular location for more than a hundred years. It doesn’t colonise new areas well, occupying strongholds in areas with traditional orchards, such as Gloucestershire, Herefordshire and Worcestershire, however, orchards in other counties like Kent have never had high levels of Mistletoe and this is thought to be down to climate. But things are changing and since 2000 it has been noticed that the distribution is increasing in eastern England. The biology of its spread is intriguing, as several factors need to be in place for a Mistletoe seed to successfully take hold – the right pollinator, the right bird and the right tree.
The right pollinator
Flowers open in February to March with male and female flowers on separate plants. It is generally insect pollinated so requires early pollinators, namely flies like Dasyphora and early flying bees.
The right bird
Mistle Thrushes have traditionally been seen as the main consumer of the berries, but many of those in the UK will never see a Mistletoe berry. Thrushes are territorial birds, so the clumps will be guarded carefully. They are endozoochorous dispersers, gobbling down the whole fruit, seeds, and all. Once they have had their fill the birds don’t travel far to relieve themselves or risk losing their territory.
Seed is perhaps ejected onto a latrine area off the end of a branch or onto a fencepost and may not meet a suitable host.
Blackcaps also eat the berries and with warmer winters have recently started to overwinter here. Blackcaps are observed to carefully remove the seed, and because it is so sticky, they are forced to wipe their beaks on the nearest surface, which is most likely to be on a branch of the same tree. The seed is more likely to be placed where it can grow, but not spread far as they also need to guard their supply.
The right tree
Seeds can germinate on all trees, but can only grow successfully on a few species. These are most often on Apple, Lime, Hawthorn, and Poplar and less frequently on species of Maple, Willow, Crab Apple, and False Acacia. Orchards are the traditional location, but fruit-growing is not so economically viable these days, leading to a decline from the loss of orchards. Having said that, some of this loss is currently being balanced by an increase in the lack of Mistletoe control in unmanaged orchards. Mistletoe is seldom seen in a woodland.
Where we have seen an explosion in population is our gardens and parks, where many of the host species, or their cultivars have been planted. Whether traditionally through orchards or more recently horticulture, the provision of host trees is highly man-made.
So, before you pucker up over the holiday season take a moment to reflect on just how complex the interdependency of our wildlife is - that Mistletoe is nothing short of a miracle! If you want to go in search of this fascinating plant, then a winter walk through Watford’s Cassiobury Park would be a very good place to start!
Feeling festive? Did you know Herts and Middlesex Wildlife Trust offer Gift Memberships enabling you to treat your loved ones to the discovery of nature, whilst contributing to the protection of our local wildlife and wild places?
hertswildlifetrust.org.uk/shop
