Rhododendron ponticum is a vigorous and invasive species of rhododendron that blooms in spring, bearing large trusses of mauve flowers. A native of western and eastern Mediterranean regions, Asia, and China, it was introduced to Britain in the 19th century and widely planted in parkland as cover for game birds. This is the only species of rhododendron that is an invasive weed, and there are literally hundreds of other species and varieties of rhododendron that make far better garden plants, without the worry of spreading into the wild.
Problems caused by Rhododendron ponticum
Rhododendron ponticum is a serious invasive weed in many wild areas, particularly in the milder and wetter western areas of the UK where it thrives in the moist climate and acid soil. Its rapid dense growth out-competes native plants and significantly reduces biodiversity. Rhododendron ponticum is also highly undesirable is because it is a host to Phytophthora fungus species that cause Sudden Oak Death which has caused the death of thousands of oak and larch trees. It is hard to eradicate as this shrub spreads readily by seed, and by layering of the stems where they touch the ground.
Rhododendron ponticum and the law
At present it is not illegal to buy or sell Rhododendron ponticum, or to plant it in a garden. However, Rhododendron ponticum is listed on Schedule 9 of the Wildlife and Countryside Act in England and Wales, meaning it is an offence to plant or otherwise cause to grow this species in the wild. You should stop them spreading from your garden and avoid purchasing or accepting gifts of these species. Any prunings or waste material must be disposed of responsibly.
How to identify Rhododendron ponticum
Rhododendron ponticum is a vigorous shrub that produces branching, woody stems, and spreads almost as wide as it grows high, the woody stems eventually forming tree-like trunks. Mature height is around 6-8m and the overall spread in the region of 6m. The large, glossy, evergreen leaves are lance-shaped or slightly broader in shape and up to 18cm long. In colour the leaves are dark green above and paler green on the underside. Flowers are borne in early summer in large trusses made up of 10-15 open funnel-shaped blooms, individually up to 5cm long. Flower colour is usually light purple but can vary from paler mauve, especially when the flowers have been open for some time, to reddish purple.
Rhododendron ponticum and wildlife
Rhododendron ponticum has significant and detrimental effects on wildlife by smothering native flora and reducing biodiversity.
Is Rhododendron ponticum poisonous?
Rhododendron ponticum contains toxins that are harmful to people and livestock. Take care when handling cut foliage, or when transporting for disposal.
