Saturday, 26 January 2013

Ivy: a feast in two acts

In my last blog, "Migrant Thrushes", I wrote of bushes being stripped of their fruits, and indeed this is true - but help is at hand. Ivy is one of the last native plants to flower, its nectar providing a final feast for many insects. As they gorged themselves on this sugary bounty they fulfilled their function of pollinating the plants and now, in the dark days of January, we are seeing the results; the berries are steadily swelling and beginning to take on purple tints. It won't be long before many creatures are again gorging themselves - not just birds such as thrushes and pigeons but mice, badgers, squirrels and even foxes will be tucking in. This is not surprising since the pith of ivy fruit is, according to the RSPB, as calorific as a Mars Bar!

There is a downside to all this: as ivy smothers the trunk of a tree virtually all mosses and lichens, starved of light, begin to disappear. This climber is not a parasite and does no direct damage to the tree on which it grows but about four years ago a number trees hereabouts, their crowns top-heavy with ivy, came crashing down in autumn gales, several of them blocking roads. It is not surprising that the growth should be so heavy for there are reports of ivy plants 400 years old.

Although we take ivy for granted, it is an intriguing plant, the only native representative of a largely tropical family, the Araliaceae. Many members of the family form lianas, those vines by which Tarzan made his way through film sets  African forests, to the delight of credulous kids like me who, intent on watching the exploits of Johnny Weissmuller, chose to ignore the strategically placed - and all too obvious - ropes.

The non-fruiting foliage differs from the leaves on fruiting branches, with pale veins making some forms popular with gardeners. John Clare inevitably observed these and wrote:

                         Save grey-veined Ivy's hardy pride
                         Round old trees by the Common side,
                         The hedgers toil oft scare the doves that browse
                         The chocolate berries on the Ivy boughs.

                                       Clare's "Shepherds Calendar", 1827
Ivy: palmate leaves on non-flowering branches
Smooth leaves on flowering branches
26 January: some fruit is almost ripe


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