More than any other form of horticulture, bonsai combines nature with art. There is art in pruning a tree so that its life is prolonged and art in shaping a tree so that, in its decorative pot, it is always pleasing to the eye. Add the further ingredient of miniaturisation - a plant that in the wild could reach 100metres, now living happily in a pot which can be held in the hand - and the art of bonsai might sound formidable, if fascinating.