Visitors to White Spire school in Bletchley, Bucks, know exactly what to do: they just follow the yellow brick road. Half way along they come across a pair of shocking pink stiletto-heeled shoes, glittering in the sun. Then they catch sight of the Lion, Tin Man and Straw Man and know for sure they’re in the Land of Oz and will probably be humming “We’re off to see the Wizard” for the rest of the day.

White Spire is a local authority special school for boys and girls with moderate learning difficulties aged five to 19. It was the pupils’ idea to create a school garden around the theme of The Wizard of Oz, after seeing the film with Judy Garland. With the staff at the school, they have ingeniously interpreted the story in art and nature and found ways of linking other aspects of the curriculum to the project.

The technology department trialled several versions of the Straw Man until they found one that would withstand the weather, and have created a brilliant Tin Man out of recycled baked bean cans. The lion’s head - his mane displayed like the rays of the sun - is cut out in wood and mounted against the wall.

Art and science meet in the constantly changing planting designs. One section uses brightly coloured bedding to depict the colours of the rainbow and changes with the seasons. Another bed is planted with ornamental brassicas to represent Dorothy’s vegetable garden; and glossy green foliage and silver plants have been chosen for the emerald city.

There is a bright yellow bench at the end of the yellow brick road, where visitors sit and enjoy the scene, pondering on the visual clues - the broomstick against the wall, Dorothy’s ruby slippers and the ivy-clad dog in a shopping basket. Cheerful, stencilled window boxes continue the theme along the front of the school.

White Spire’s Wizard of Oz garden was the Thames Valley regional winner in the Greenfingers Challenge, run by the Tidy Britain Group and the Royal Horticultural Society. The competition, about to be launched for its second year, aims to raise children’s environmental awareness by challenging them to carry out a project that improves their community. It is open to all schools and youth groups, and more than 700 responded to the call to “be creative and take action”.

“The whole school has been lifted by their success,” says headteacher Jim Moore. “The pupils are made very aware of the importance of creating a pleasant environment and worked hard during the holidays to keep the garden up to scratch.”

Support assistant Lynda Castle, the driving force behind the White Spire project, says everyone in the 163-pupil school has been involved and that the garden has caught children’s interest in different ways. It has given them a real sense of achievement to see things grow, and inspired high quality work in art, science and technology. Some have been helped with language work, while others have gained confidence with physical skills.

Plants have been propagated for fund-raising; tomatoes harvested for chutney; and sixth-formers have developed horticultural mini-enterprises for their vocational courses. Parents and garden centres have contributed help and expertise, and there are now plans to develop some of the other green spaces around the school - with a sensory garden or maze, for example.

Gardening has become the starting point for many learning activities, says Jim Moore - “It’s not just an add-on.” The prize money will be ploughed back into more horticultural work.

Details of next Greenfingers Challenge are available from Tidy Britain Group 01942 824620