Healthy soil and sustainable growing

["Douglas Willhite" <drwillhite@earthlink.net>]

Written for British gardeners, but contains useful information applicable here. Doug

How to get a buzz out of your garden

Friday April 20, 2007
Guardian Unlimited

Bumblebees are under threat from disease, pests and habitat loss, but it's not too late to halt the decline. Carolyn Fry suggests some simple steps the green-fingered can take to save Britain's best-loved insect.

 

The stop-start hum of bumblebees gathering nectar from flowers in our gardens is a familiar summertime sound. But it could become a thing of the past if an alarming decline in bee numbers cannot be halted.

Of the 25 species of bumblebee that are native to Britain and Ireland, three have already become extinct, two are close to extinction and a further nine are declining. Intensive farming methods that have destroyed hedgerows and hay meadows and increased the use of insecticides are the main culprits.

Meanwhile our sole species of honeybee, Apis mellifera, is under attack from the varroa mite that arrived from Asia 15 years ago, and a mysterious phenomena called colony collapse disorder (CCD) that has begun decimating populations in the USA and parts of Europe.

The decline has alarmed experts because bees play an important role in pollinating fruit trees and other crops. They are calling on gardeners to help reverse the population losses by providing suitable habitats for these much-loved insects.

"There are around 1m hectares of gardens in the UK which form an area way bigger than all the nature reserves and parks put together, says David Goulson, director of the Bumblebee Conservation Trust at the University of Stirling. "They vary in their attractiveness to bees, as some plants are very useful and others are not. We're trying to encourage people to grow more of the right kind of plants."

These tend to be traditional cottage garden plants such as lupins, hollyhocks and lavender. They offer a ready supply of pollen and nectar from flowers that are easily accessible to passing bees. Of less use are cultivated annual bedding plants that have been highly bred. These often produce no nectar or have double-headed flowers that make access impossible for insects. You can find a list of plants favoured by European bees at bumblebee.org.

As well as selecting the right kind of plants you need to make sure your garden has some plants flowering throughout the year. "It's important to have flowers on the go from early spring through to autumn so the bees have a constant supply of nectar," says Adrian Knowles, an ecologist with Essex Wildlife Trusts and Suffolk's county recorder for bees and wasps.

Providing a safe haven for the winter months can also help bees to thrive. Many bumblebees nest at or below ground level, especially in old mouse holes. You can simulate this environment by sinking an upturned flowerpot in the ground and covering it with a lid. Bees can then build a nest in the subterranean chamber you have created.

You can also buy specially designed nesting boxes for bumblebees. With two compartments, these are designed to attract nest-seeking queen bumblebees in early spring, which will use them to rear a colony during the summer. They are available from many garden centres or you can order them online from the Nestbox Company.

Alongside the communal-living bumblebees and honeybees, more than 200 species of solitary nesting bee also dwell in the UK. Some frequent our gardens but being small or medium-sized, they often go unnoticed. These bees nest independently in small holes and crevices in walls, dead twigs or the ground.

Solitary bees include the red mason bee Osmia rufa, which is an important pollinator of garden herbs and commercial crops. You can encourage this bee to overwinter in your garden by installing a different type of nest, comprising a bundle of thin tubes. You can either buy one or make your own from a bundle of short bamboo canes placed in a length of guttering. These nests may also attract blue mason Osmia coerulescens and leaf-cutter bees.

Once you have begun attracting bees to your garden you can help the Bumblebee Conservation Trust survey the numbers of different species by keeping records of what you see. The British Trust for Ornithology (BTO) has added bees to its Garden Birdwatch where you can upload your own observations.

If you don't feel able to identify bee species yourself, you can send a digital photograph of any unknown specimen, along with the postcode and date of the observation, to the Bumblebee Conservation Trust. They will tell you what species you have spotted and include the sighting in their survey.

You are most likely to see one of the six bumblebee species that are presently thriving across the UK. However, taking measures to encourage bees could well encourage the declining species to take up residence in your garden.

"Some of the rarer species do come into gardens and I think if gardeners are more bee friendly they will visit more often," says David Goulson. "There's every chance we could have lots more species living alongside us."