Gardening for bees

Issued June 2004

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Gardens can offer good habitat for a number of insects, including that most beneficial group of insects, bees. Most adult insects depend on flowers for nectar, but bees collect pollen to feed their young as well, and in doing so pollinate the flowers. Most people think of honeybees here, but these are actually less useful in this respect than bumblebees and solitary bees, which pollinate a much wider range of flowers.

Bumblebees – in decline

Like honey bees, bumblebees live together as a colony and cooperate to raise their young — they are social insects. The colony always centres on the queen, who lays eggs most of which develop into workers. The workers look after the queen, and help to raise more young and build up the colony. A colony of honey bees may run into tens of thousands but colonies of bumble bees are much smaller – 200 workers at most. Unlike honey bees, which survive the winter as a colony, bumblebee colonies die out in the summer or early autumn and only the young queens raised towards the end of the summer survive, hibernating through the winter and waking up in spring to found a new colony from scratch.

Bumblebees often nest in gardens, under shed floors and under decking being favourite spots. They are docile and unaggressive creatures even near the nest, so no more a threat to children or pets when they nest in your garden than if just visiting the flowers, although curiosity may lead them to inspect you in case you might be a source of food. The commonest reason for stings is self-defence such as when bees are trodden on or squashed by mistake.

Only six bumblebees remain widespread in Britain, and these are nowadays often more abundant in gardens than in the modern ‘brown’ agricultural countryside. They can successfully use flowers as nectar and pollen resources in gardens, and are far more important as pollinators of fruit trees and many other flowers than honeybees. However even these common bumblebees tend to collect pollen from a rather restricted range of plants, and you can help them by providing the right kind of flower resources. As well as fruit trees in spring and early summer such as apples, cherries, plums and currants, any flowers in the pea and labiate families are good, and some particularly useful plants to grow are listed below.

Solitary bees

Many other species of bee that visit gardens are solitary, rather than social like the bumblebee. In summer they make a nest, usually in a hole in wood or in the ground, lay eggs in it and provide provisions in the form of honey or pollen, then die off as the cold weather arrives. The eggs hatch the following spring or early summer and the young bees then find a mate and the cycle of egglaying begins again. Solitary bees therefore do not survive to see their own young develop.

There are many species of solitary wasp that have a similar lifecycle, the key difference being that they provide live meat to feed their young, typically stinging a caterpillar to paralyse it and keep it fresh until eaten the following spring.

One of the commoner solitary bees in gardens is the leafcutter bee (right), which uses pieces cut from leaves to line its nest in a hole in wood. Another frequent bee in gardens is a tiny black species called Chelostoma campanularum, which collects its pollen from garden harebells (Campanula species), and the Tawny mining bee Andrena fulva is a beautiful solitary bee that is an important pollinator of fruit trees in spring. If you want a good fruit crop, hope this bee visits, and even better, nests in your garden! The female is very characteristic in appearance; it has orange-brown hairs over the thorax and abdomen and black hairs on the face, legs and sides. This bee is still widespread, but almost certainly less common than in the past.

Artificial homes

Leafcutter and other bees will readily adopt artificial homes. Cut some (untreated) 5cm x 5cm softwood into 20 cm lenths, then drill several holes 8mm—10mm in diameter and 15 cm or so deep into one end. Strap several of these together and hang them under a bush or under the eaves of a low building, well sheltered and with the holes south-facing. Be patient because they seem to be more acceptable to bees when weathered. Inspect them in the summer and you will be able to see when holes have been used for nests and also when the young have hatched and dug their way out, after which you can redrill or clean out the holes. Commercial nests are available also, including from Essex Wildlife Trust visitor centres.

All bumblebees need for a nest site is a waterproof, well insulated, undisturbed space about the size of a football. They will adopt any suitable spot that is accessible, including in a roof, under a shed or decking, in a loose, dry compost heap or in an old mouse nest underground. Occasionally they will even use birdboxes.

To create an artificial nest bury a large clay plantpot in the ground with a 25mm pipe or hose running from the drainage hole to the surface. Or you can make a box about 20cm high and wide and 35cm long, with a wood or perspex cover and divided into two about a third of the way along. Drill 25mm entrance holes through the smaller compartment and put nesting material such as dry leaves or kapok in the larger, plus a few ventilation holes. Put it in a sheltered spot in the garden covered with roof tiles or slates to keep out the rain.

Flowers for bees

Double flowers are of no use to insects, since they do not provide nectar. Even plants with single flowers may be of limited use if they are not native to Britain. The most valuable plants are those in the pea family, dead-nettles, mints and scented herbs, the figwort family, and the daisy family. In spring and early summer fruit trees provide an important resource – indeed the crop will depend on solitary bees and bumblebees visiting and pollinating the flowers.

If you can bear to leave a few ‘weeds’ to grow and flower in the garden, then you can do even better. Red deadnettle, black horehound and yellow composites such as dandelions and hawkweeds can bring in some real rarities. If you live within the range of some East Thames Corridor specialities (as in Havering, Thurrock or Southend) you may tempt a few rarities into your garden The Brown-banded carder bee Bombus humilis will forage, for example, on runner bean flowers, and the nationally scarce mining bees Andrena fulvago and the black Andrena spectabilis may be regular visitors foraging on Crepis and Hebe flowers respectively.

As well as providing a range of nectar and pollen resources, try to leave some dead wood, leaf litter and dead stems in undisturbed corners of your garden. Try not to be too tidy! Earth banks, fences and walls with old mortar in the sun are also important nesting habitat for bees. Various insects and spiders will also use them to warm up early in the year and in the early morning.