How to Rewild

Rhododendron Scrub

Habitat Management Plan

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Rhododendron Scrub
Habitat Guide

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A single highly-invasive shrub is estimated to cover at least 37,000ha of England, with more in Scotland and Wales, and landowners can be legally-compelled to remove it from their property.

Sub Habitats

Acid soil habitats dominated by the invasive non-native shrub Rhododendron ponticum.

How to Identify Rhododendron Ponticum

An evergreen plant; most of the Rhododendron which covers the UK is thought to be one species – R. ponticum. This is naturally found in Spain and Turkey, but was widely-planted by the Victorians due to its showy pink flowers and attractive form. Unfortunately, the plant is very invasive, spreading via seed, and growing back vigorously from cut stumps.

Rhododendron
The showy pink flowers and evergreen leaves make Rhododendron ponticum quite distinctive and hard to mistake for a native species

Why to Remove R. ponticum

Without control, a habitat containing one R. ponticum will soon contain little else. The plant has 3 tricks up its sleeve which allow it to spread rapidly as a monoculture. The leaves are toxic to herbivores, so it isn’t browsed back by deer; it produces a phytotoxin in the soil that poisons other plants; and its evergreen leaves create shade so dense that little else can grow beneath it.

R. ponticum is also a vector for two diseases which are rapidly spreading across the UK; Phytophthora ramorum and P. kernoviae. Due to this, and the invasive nature of the plant, there are grants to landowners that will help cover the cost of control work.

How to Control R. ponticum

Once R. ponticum is established, most attempts to remove it will be only partially successful unless they continue for many years. Given that the plant can come back from cut stumps and from seeds, experiments across many different woodlands have shown that it is able to resist fire, weedkiller, grubbing out, flailing and cutting back.

However, the most effective strategy is combining two of these methods and repeating the strategy for multiple years until no regeneration is seen. The two methods which, in combination, are most effective, is cutting at the base (ideally below the lowest leaves), and then treating the stumps with weedkiller.

While we typically advise against using herbicides due to the impact on the soil and plant community, in this case, the alternative (a monoculture of R. ponticum) is far worse for biodiversity. Conservationists are using this approach and have found it is very effective at controlling the plant, especially when repeated over a number of seasons.

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