July Nature Watch

June 26 2015

Gardeners sometimes find themselves in opposition to certain sections of the biological diversity that shares our city.

with Dawn Lawrence

Gardeners sometimes find themselves in opposition to certain sections of the biological diversity that shares our city. However, in a well-balanced ecosystem every pest has its predator and some of our favourite garden visitors think of those pests as lunch!

Blue tits and great tits prefer to feed their young on caterpillars, and gardens provide them with good supplies at the right time of year; later they will move on to aphids. Ladybirds, those most cheerful and child-friendly of beetles, are always on aphid patrol. We once found a thrush’s anvil in our garden; a large angular stone against which the thrush had been busy breaking the shells of snails plucked from our flower beds. In return for those snails, he sings us his tuneful and inventive song. Slugs are much less palatable to birds, though once, in a dry spell, we watched a blackbird wiping a big slug against a brick to remove the slime before gulping it down with a look of distaste in its beady yellow eye. However, the violet ground beetle loves the taste of wet slug on a cold morning. These beautiful beetles have black wing cases tinged with violet with a shining edge when they catch the light.

Some species acquire an undeserved notoriety amongst gardeners. Many dislike the rose chafer beetle because of its reputation for eating rose petals and, in the words of one disapproving gardener “because they do buzz so!” For me their buzzing is a pleasant musical accompaniment to warm summer days, but it is true, they will eat rose petals as a part of their diet. However, they also are brilliant at making compost – this is junior beetle’s job. Find a big fat grub in your compost heap? Think, “oh yuk!” or maybe even, “hmm... perhaps sauté with garlic and ginger?” Stop! This ugly grub is no idle squatter, it is busily turning your garden waste into valuable compost. And then it will turn itself into a sparkling metallic green beetle and go and fly into a garden wall and land upside down on the pavement, where it will catch your eye as it lies there wriggling its golden-rose underbelly (they’re not great fliers!). So please, don’t crush it: pick it up and place it on a flower. It’s done sterling work making compost for most of its life, surely we can spare it a few bites of rose petal in return during its few weeks of adult life.

Now, I’m not going to claim that installing a couple of tit boxes in your garden will sort out your aphid problems and nor will the ground beetles ever eradicate the slugs but it is worth choosing a specific molluscide to apply to your slugs, and an aphidicide for your roses rather than a wide spectrum pesticide which will kill off your ground beetles and ladybirds as well as your slugs and aphids. And it is worth installing a bird box for the tits, if only for the sheer pleasure of watching them!