The Holly and the Ivy….

Friday, December 19th, 2014

Both holly and ivy are excellent sources of winter foraging for a range of species from birds to mammals to invertebrates as well as providing a welcome splash of green (and red) in the otherwise monotone winter landscape. Ivy flowers are one of the few sources of nectar for late flying butterflies and other insects in the autumn and the fruits of both holly and ivy are a plentiful food source for birds in the winter.

Holly Blue Butterfly

While holly has been revered in folk traditions for centuries and boughs are regularly collected for Christmas decorations, cutting down a holly tree is thought to bring bad luck. Perhaps this is because the holly is dioecious, i.e. only the female plants bear fruit. So, while you can ‘deck the halls with boughs of holly’, if you cut down a female or even a male tree you reduce the chance of berries being produced. In order to see (and use) the red berries at Christmas one male tree should be planted with several female for good fruit production.

However, people are more ambivalent toward ivy, it is frequently accused by foresters of killing trees, by out shading the trees own foliage or by weighing down the tree and causing collapse. In the past though, there were those who believed that the ivy’s ability to smother grape vines indicated that its berries could counteract the less beneficial effects of alcohol, perfect for the festive season! More importantly though, ivy is essential to some invertebrates, in particular the ivy bee Colletes hederae which restricts its search for pollen to ivy. This bee has expanded its European range in recent years. First recorded in Dorset in 2001 it has now spread across southern England and is unusual in having such a late flying season.

And what about mistletoe, the other plant closely associated with Christmas. Mistletoe is a semi parasitic plant most commonly found on old apple trees that provides food for specialist birds such as the aptly named mistle thrush and blackcaps.  The two birds eat the mistletoe berries in different ways, the mistle thrush eating the berries whole and later excreting the seed, while blackcaps try to wipe the seed from the sticky flesh of the berry onto the branch of the tree.  As a result the blackcap’s method is much more reliable in spreading mistle from tree to tree and helping it to germinate.  While mistletoe is locally common in the UK, its distribution has declined alongside the demise of traditional orchards. Mistletoe is a London BAP priority species and LBAP species across some London boroughs, while traditional orchards are BAP priority habitats.

We need to look after our winter plants, after all what would Christmas be without them?

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