Rhododendron ponticumcan form very dense thickets and out-compete native plants for space and resources, especially for sunlight. Other impacts on fish and invertebrate communities have been recorded. Rhododendron can also prevent access to sites by the shear mass of plant material blocking paths and right of way.
The species is found in various habitats including mixed deciduous forest, temperate heaths and raised and blanket bogs. A native to both Europe and Asia, it is believed to have been first introduced to parks, gardens, and demesnes in Britain and Ireland in the 1700’s.