WITH the start of December I am trying to choose Christmas cards and determined to actually write and post them before Christmas Eve. Whilst picking my way through the myriad of seasonal charity cards, I was struck by how many showed images of native plants such as holly and mistletoe and it got me thinking about their natural history in addition to the usual folk tales, myths and legends (described in detail in Richard Mabey’s Flora Britannic – well worth a read).

Images of holly will be found in nearly every household celebrating Christmas and it is a plant that we all know and love although possibly not when pruning! Holly is sought after in the dark winter months because of its bright red berries shining like jewels in bare hedgerows. However, not all holly bushes have berries because individual bushes are either male or female and only the female plants will have berries.

Holly bushes, unlike many other native plants, can retain their berries into late winter and are helped in this by their very own security guard - the Mistle Thrush. Pairs or individual Mistle Thrushes will set up territories in laden holly bushes which they then defend from all other birds to ensure a source of food throughout the winter.

So if you pass a particularly bright bush in a hedgerow this Christmas have a look and see if it is guarded by a resident Mistle Thrush.

Remnants of holly remain in many of our hedges where they once formed part of a stock proof boundary and, being evergreen, also provided some shelter in winter. In the Pennines the upper branches were traditionally used as fodder for livestock to supplement dwindling winter hay supplies. Holly has very spiny leaves to protect it from grazing, however higher up, the leaves are less spiny and it is these higher branches that were cut and used to feed the sheep.

Less showy than holly, ivy is another evergreen that is used in winter decorations. Although common and often dismissed, ivy is equally fascinating when studied a little closer. It is England’s only native evergreen climber and climbs upwards in order to reach the light above the tree canopy.

Like holly, it has different shaped leaves depending on the age and position of the shoot, this is known as dimorphism. The young growth has the traditional ivy shaped leaves which are adapted to low light conditions. More mature plants, however, can produce bushy shoots with more oval shaped leaves that require more light and are rarely found close to the ground.

Although used to illustrate Christmas cards and wreaths, ivy is hated by many people who mistakenly believe that it strangles and kills trees but ivy is not a parasite and produces all of its own food, the tiny hair like roots only being used to grip onto the bark for support. Often on a winter’s walk you may see trees that appear to be overwhelmed by ivy but this is usually on a tree that is already stressed.

A healthy tree canopy will not let enough light through for the ivy to grow vigorously. If a tree is already in decline the added weight of ivy in the crown may potentially create a safety hazard but if not the ivy should be left alone. In my opinion nothing looks worse than a tree full of dead ivy (which happens when the stems are cut at ground level), not only is it ugly but it is removing valuable evergreen shelter for birds, insects and even the occasional bat. In addition the ground cover provided by ivy can reduce frost and snow allowing thrushes and blackbirds to forage underneath.

Mistletoe, much loved by the more romantic of you is semi-parasitic and takes nutrients and water from its host tree. Mistletoe is mainly found in the South Midlands where it grows on apple trees in traditional orchards although it can be found on other species such as lime and hawthorn. The decline in traditional orchards has led to the loss of mistletoe and many other associated insects, fungi, plants and lichens and the Wildlife Trusts are currently campaigning to halt and reverse this trend.

The poorer climate and lack of orchards means that mistletoe is uncommon in our region although I have seen some at Parcevall Hall. However, this may be changing as recent surveys have revealed that the range of Mistletoe is expanding due to climate change or possibly due to the changing habits of a small bird called a Blackcap. Mistletoe can only grow when seeds land directly on a branch often in bird droppings (again mistle thrushes are the main culprits) or when Blackcaps eat the berries and wipe the sticky seeds from their bills onto the branch. British Blackcaps used to migrate in winter and so did not eat and spread mistletoe but with climate change Blackcaps have started overwintering in Britain and are now contributing to its spread.

In the past, mistletoe was seen as a problem for orchard owners as it could weaken trees. Now, with increasing Christmas demand, it is becoming a valuable commodity and organisations such as the National Trust are urging us to choose English mistletoe to help with the future survival of traditional orchards.

So if you should find yourself under mistletoe at the office Christmas party be sure to check it is English!