A campaign to encourage people to grow bee-friendly flowers in their gardens has been launched at Kew Gardens.

Around 20,000 honeybees have been released into two hives in a wildflower meadow at the world famous botanical gardens in London, marking a return after a year without the insects.

Bees in Kew's hives died at the same time as many colonies across the country - with the widespread losses thought to be as a result of problems including disease and environmental pressures.

Bees play a vital part in pollinating many of the crops grown in the UK, but have been hit by agricultural changes which have reduced the availability of the wildflowers that are so important in providing food for the insects.

Diseases such as the varroa mite have infected hives, killing the bees, while climate change and pesticide use have also been suggested as possible factors in the insects' decline.

The number of honeybees has fallen by 10 to 15 per cent in the last two years, according to the Government.

But a survey of British Beekeepers' Association members suggests losses could have been as high as 30 per cent between November 2007 and March 2008.

Annette Dalton, horticultural manager at Kew Gardens, said: "No English garden is complete without its bees and Kew Gardens is no exception."

© Independent Television News Limited 2009. All rights reserved.