There are certain insects (plus the humble worm) that we gardeners cannot do without. Wasps may have a use after all, in that they are voracious killers of caterpillars, aphids and other invertebrates. Ladybirds, hoverflies and lacewings all put aphids high on their menu. Ground beetles eat slugs and snails (hooray for them!).
Bees have been in the news of course, as their numbers have plummeted worldwide. Much of this has been laid at the door of a virus spread by the Varroa mite. Whilst this has undoubtedly been a major factor, there is no doubt that a lack of food, plus the longer term effect of pesticides, have eroded bees resistance to this, and other viruses. The major issue, and one we can do something about, is the impact of pesticides. Please don’t use chemicals that contain “Neonicotinoids” – avoid pesticides altogether if you can.
What else can we do to help them? Bees, and other pollinators, need 3 key things – food, water and shelter. Water is easily provided - if you have a pond or bird-bath then you have already ticked that particular box!
For shelter - log piles are attractive to all sorts of wildlife. Drill holes of varying diameter (2-8mm) in the ends and this will attract bees – especially if sited in the sun. A log-pile in the shade will remain cool and moist – good for beetles and amphibians. To create the best habitat for the widest variety of wildlife, use logs from local, native trees, but if you can’t get hold of any, use whatever you can find — even sticks or bought logs destined for a wood-burning stove. Partially bury the bottom layer and fill a few gaps with fallen leaves, moss and soil.
Leave untidy bits of the garden – especially in the winter, where dying plants and rough grass provide excellent shelter. Your own compost heap is both a preferred source of plant nutrients than peat, and a brilliant shelter for wildlife. Climbing plants are a great source of shelter, where insects can hide from their enemies amongst dense foliage.
Food sources for wildlife should be varied and provided over as long a growing season as possible. Early flowering plants are of particular importance to wildlife coming out of hibernation.
Grow nettles! Even a small patch of nettles will attract the nettle aphid which will, in turn, attract aphid-eating ladybirds to your patch. The nettle aphid only visits nettles, but because it emerges earlier than other aphids, it brings ladybirds to your veggie patch long before other aphids have had the chance to build up their populations on your roses and broad beans, so they’re on hand to tackle early infestations. The stinging nettle is one of the UK’s most important native plants for wildlife. It supports more than 40 species of insect including some of our most colourful butterflies. Nettles can also be a useful part of our diet - used as a blood purifier, and high in iron and potassium.
There are a number of flowers and herbs that will serve well to attract all types of insect. I have identified some of the most beneficial (i.e. attract ladybirds, lacewings, hoverflies, ground beetles) below (all are pretty easy to come by and to grow):
Cornflowers - has extrafloral nectaries, which means the plant's leaves release nectar even when the flowers are not blooming. Research in Germany has found that cornflower nectar has a very high sugar content of 75 percent. This nectar is highly attractive to many insect species.
Borage – an annual herb with bright blue clusters of edible, cucumber-flavored flowers. Studies in Switzerland have shown borage to be exceptionally attractive to good bugs, with an average of over 100 beneficial insects found in just 1 square yard of borage. In addition, common green lacewings have a very strong preference for laying their eggs on borage.
Anise Hyssop (aka Korean mint) - perennial, summer-blooming with fuzzy purple or violet flower spikes on 2 to 3 foot high plants with licorice-scented leaves. The nectar-rich flowers are very attractive to both butterflies and pest-eating beneficial insects. It self-seeds and spreads quickly making it an ideal choice for filling in sparse areas of your garden. At the same time the seedlings are easy to pull so it is simple to weed out any extras that have grown where you don't want them. In fact, weeding them out is actually quite a pleasure thanks to the pleasant aroma.
Fennel - Long-lasting fennel flowers are extremely attractive to all nectar-feeding beneficial insects, and the feathery green or purple foliage looks wonderful in spring and early summer.
Foxglove – bumblebees love them!
Thyme - This herb provides excellent ground cover in gravel gardens, creating safe spaces for beetles and other invertebrates. Its nectar is also a favourite of bees.
Lavender - The calming scent of lavender on a sunny patio is a magnet for bees and butterflies. When the purple blooms go to seed, birds can tuck in.
Honeysuckle - This climber buzzes with visitors in the summer months, attracting nectar-loving insects including the hummingbird hawk moth. Warblers and thrushes enjoy the berries.
A strip of flowering plants — particularly umbellifers such as fennel, angelica, dill and coriander — will attract hoverflies and lacewings, whose larvae feast on aphids. Angelica is also thought to attract common wasps, which will destroy anything from aphids to caterpillars and other flying pests.