Ivy is a self-clinging climber whose tiny, adventitious roots allow it to attach to trees or walls. In woods it can also carpet the ground. It has glossy, evergreen leaves with three or five points which give the characteristic ivy shape. It is a useful plant as it grows in any soil, in shade or sun. However, only shoots in the sun produce flowers as well as unlobed leaves which look as though they are from a different plant. Small leaved and variegated ivies are available in garden centres.
It is poisonous to humans but exceptionally useful for wildlife. Small greenish nectar rich flowers are produced in autumn. The blackish berries ripen in late winter. The seeds are dispersed by birds which eat the berries. Wasps, hoverflies, bumblebees and late-flying butterflies feed on the nectar. Ivy is not a parasite and does not strangle trees though a heavy growth can make a tree unstable. It is often said that ivy growing on walls will cause damage to the wall. This is not entirely correct. Walls in good condition are impenetrable to the roots but walls with loose mortar may be damaged.
For those of you who may have overindulged over the festive period, this tip may be of some interest to you. Wearing an ivy headband was said to prevent a person from getting drunk. The Roman god Bacchus, the god of intoxication, was often shown wearing a wreath of ivy and vine leaves. Ivy was a symbol of fidelity and priests would present a wreath of ivy to newly married couples. This is a tradition carried on today with some bridal bouquets still containing a sprig of ivy.