RHODODENDRON : Rhododendron ponticum
Rhododendra (or rhododendrons) come in a wide range of colours and continue to be very popular in gardens. Simply because you find one that is purple does not mean that it is the problem species, but it is the problem species that is purple.
One species of rhododendron in particular, Rhododendron ponticum, has become a great problem. This is a hardy shrub that can grow very large. It has lovely purple flowers. But is one of the most challenging to eradicate once established.
Gardeners World notes that it is 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. The grand estate woods and gardens of Overtoun House are a good example as are those of the original Kilmahew Estae near Cardross. In both cases these shrubs grew into amazing and large displays of purple. The latter still has a great "tunnel" of large plants through which you can walk. In both cases though efforts are made from time to time to eradicate all those that have crept beyond their intended domain.
Avoiding planting Rhododendron ponticum is strongly recommended.
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.
At present it is not illegal to buy or sell Rhododendron ponticum, or to plant it in a garden. However, Rhododendron ponticum is listed under Schedule 9 of the Wildlife and Countryside Act 1981, which means it is illegal to plant it in the wild or to allow it to spread from your property. Any prunings or waste material must be disposed of responsibly.
If you have inherited a magnificent purple Rhododendron ponticum on your property, there is no need to panic and hack it out. But if you don't you have also inherited the responsibility to stop it spreading. That may need drastic action.
A rhododendron ponticum bush on the upper Leven.
Compare that above to this one which is so similar, but has larger flowers and more strongly defined markings to the rear petals.
GARDENERS WORLD : https://www.gardenersworld.com/plants/rhododendron-ponticum/
THE INDEPENDENT : https://www.independent.co.uk/climate-change/news/rhododendrons-invasive-species-temperate-rainforest-b2108031.html
THE SPRUCE : https://www.thespruce.com/naturalized-plants-flora-of-locale-2131090
WIKIPEDIA : https://en.wikipedia.org/wiki/Naturalisation_(biology)
