BUILDERS' hats blooming in steel poles like yellow buttercups and a telly-tubby mound with a fuchsia pink wall inside... the second International Festival of Gardens at Westonbirt has just opened...

In interior designer Deborah Nagan's garden, a metal tube suspended by a chain splashes water onto a rusty barrel filled with scaffolding clamps.

Around it is a fence made of the scaffolding poles themselves, some with builders' helmets blooming on top like yellow buttercups.

Scrap metal may not be everyone's idea of what makes a garden, but then that is the whole point of the International Festival of Gardens at Westonbirt Arboretum, to try and make us all rethink our ideas.

One of only three garden design events of its kind in the world, the festival is dedicated to championing contemporary, conceptual gardens.

Last year, sadly, with one of two beautiful exceptions, the festival looked less like a show case for innovative ideas and more like the remains of some art student party involving glass chippings, plastic windmills and a lot of alcohol. But this year all that has changed.

From the curving grass amphitheatre surrounding a sycamore planted by the arboretum's founder in 1890, to the geometric garden opening onto flat grassland, the 14 gardens, chosen from over 200 submissions, are both perfectly staged and beautiful in their own right.

Particular favourites were the Screen4 garden where iridescent, hinged screens change with the light and Neil Wilkins' steel and glass Tree of Life, but I can honestly say, strong though some of the gardens are, they are all exciting.

However, visitors shouldn't go expecting to get planting ideas. On the whole, the gardens are more about architecture than flowers. They also need to be prepared for some terribly pretentious explanations of the gardens on the information boards. They can do strange things to your mind.

The Westonbirt show is not Chelsea. The 14 designs chosen came not just from garden designers but from theatre and interior designers and painters, their budgets are limited to £15,000 and the gardens are designed to grow between now and September.

But, on this year's showing, it has the potential to become as famous a gardening event - and it's right on our doorsteps.

The festival runs until September 7.