Ivy is such a good late source of food for many insects and is a habitat in itself, the shelter it provides in its twisting vine like stems.
About this species
Common ivy is a popular ornamental, valued for its ability to thrive in shady places, provide excellent groundcover and cover unsightly walls, sheds and tree stumps. Many cultivars are available, including variegated forms that can be used to brighten shady depths of winter gardens.
Long collected for winter decorations, common ivy is associated with Christmas and frequently features in festive designs. It is also an important source of food and shelter for wildlife during winter.
Ivy is not a parasite, does not normally damage sound buildings or walls, and is rarely a threat to healthy trees. Regular trimming can prevent ivy becoming too heavy, a problem that can be exacerbated by the additional weight of rain and snow.
The Knopper Gall is caused by a tiny gall wasp, Andricus quercuscalicis. It produces ridged outgrowths on the acorns of our native Pedunculate Oak; forming in August they are sticky and red, later becoming woody and brown. A second generation then develops in the catkins of Turkey Oak.
How to identify
Unmistakeable: the Knopper Gall is a nobbly, bowl-shaped protrusion from acorns.