Most of us associate the plants known as rhododendrons with the big, broad-leaved shrubs laden with traffic-stopping trusses of showy springtime flowers.

There is an enormous variety of rhododendron forms. At one extreme are tiny miniatures and ground-hugging prostrates suitable for the rock garden, such as Rhododendron trichostomum with its twiggy shrubs and the Burmese R. forrestii. At the other end of the scale are forest trees which include R. arboreum and the largest of the genus, R. sinogrande, whose massive leaves can reach over 1 m (3 ft) in length.

Most of these cool-climate evergreen species with their colourful blooms are found in the Himalayas, southwestern China and northern Myanmar, giving rise to the term 'Asiatics', but others are also scattered across northern Asia, Europe and North America.