This popular evergreen garden shrub is naturalised in our countryside and is now widespread and common throughout the UK and Ireland.
The brief period of beauty of rhododendrons in bloom (in June) carries a high price: they spread rapidly and provide very poor habitat for wildlife.

Because they let so little light through to the ground, smaller plants cannot survive beneath the canopy.

In this picture, rhododendrons have colonised one bank of a small stream and denuded it of in-stream and marginal plants.
At Ynys Hir, in the Dyfi Valley in mid Wales, RSPB and Environment Agency Wales have cleared rhododendrons from some twelve hectares of heathland and bog to allow native species to recolonise the area.