Things to look out for in the garden - August

The garden will be emptier of flowers now, as fruit begins to set and the native flowers go over, leaving the African and other tropical species to show their glory. It's also the time when we start to find different kinds of growth in the garden and surrounding areas, including the bizarre range of growths that are found on oak trees.

Oak apple galls are sometimes mistaken for an actual crop of the tree, but are actually deformed leaves. The gall is round or slightly bulbous, and smooth, the outside begins as a very light green and darkens with age, often becoming rosy in colour, hence the apple name. Inside a gall has a juicy, white, spongy substance with a small, hard core where the parasite is located. When the parasite leaves the gall, the gall dries out. Alternatively, marble galls are green or brown spherical woody galls of up to an inch in diameter. More than thirty species of gall wasps occur in Britain on the common oak, and each species lays its eggs in a particular structure on the tree - the roots, bark, buds, leaves, catkins or acorns. Chemicals secreted by the wasp grub alter the normal cell division process and cause the plant to produce gall tissues that enclose the grubs, which feed on a nutritious layer of cells within the galls, where they eventually pupate and turn into adult wasps. The wasps do not cause any serious damage even when abundant and do not need to be controlled.

Many fruit trees, both wild and cultivated, are ready to yield their crops now, so it's a good time to examine your surroundings for wild plum trees whose fruit makes a superb jam.

Garden August oak apple photograph by Akuppa, used under a creative commons attribution licence.

garden month water visitors, garden month april, garden month august, garden month bees, garden month birds, garden month birdwatch, garden month breathingplaces, garden month butterflies, garden month december, garden month dragonflies, garden month february, garden month fungi, garden month hedgehog, garden month insects, garden month invaders, garden month january, garden month july, garden month june, garden month mammals, garden month march, garden month may, garden month moon, garden month november, garden month october, garden month september