Invasive rhododendron

Ecological impacts

Non-native rhododendron:

suppresses Native Plant Growth
Rhododendron forms dense thickets that block sunlight from reaching the forest floor. This shades out native plants, preventing their growth and regeneration. Over time, this leads to a loss of biodiversity.
alters Soil Chemistry
Its leaf litter is acidic and decomposes slowly, which can change the pH and nutrient composition of the soil. This makes the environment less hospitable for many native species.
produces Toxic Compounds
Rhododendron leaves and roots release allelopathic chemicals—toxins that inhibit the germination and growth of other plants. This gives it a competitive advantage over native flora.
harbours Plant Diseases
It can act as a reservoir for pathogens, such as Phytophthora ramorum, which causes sudden oak death and affects a wide range of tree species.
reduces Habitat Quality
By displacing native plants, rhododendron reduces the availability of food and shelter for native insects, birds, and mammals, disrupting the entire food web.
is difficult and Costly to Remove
Its resilience and rapid spread make it hard to control. Mechanical removal is labour-intensive, and chemical treatments can have unintended environmental consequences.

Scottish Forestry is working with partners to tackle the rhododendron problem in key areas.

These partners include private landowners and organisations involved in the Alliance for Scotland’s Rainforest.

The Forestry Grant Scheme (FGS) in Scotland offers financial support for rhododendron control within woodland areas.

Landowners can apply for grants to remove invasive rhododendron.

The FGS is administered by Scottish Forestry and is open to various land managers, including:

A detailed Rhododendron Control Plan is often required. This should:

demonstrate a long-term strategy for eradication and control
- including monitoring and follow-up treatments

Applicants should read the following documents before applying for grants to control rhododendron.