Field Notes: A prickly subject

John MacRae, the Trust’s Skye Manager, reports on surprising results from invasive non-native species (INNS) survey.

When the Trust brought in a woodland consultant to survey the extent of invasive non-native plant species at Strathaird on the Isle of Skye, some of the results were surprising.

We’d always thought it was rhododendron ponticum and fuchsia that posed the biggest challenge, but not so. Instead, the survey identified that our biggest problem is the abundance of a plant called pernettya mucronata (prickly heath pictured), which spreads rapidly and can quickly swamp other ground plants and colonise woodland.

A flowering shrub native to South America, and often introduced to areas as a garden or park plant, prickly heath thrives in the same acidic soils as heathers and can be incredibly difficult to remove. One method involves cutting and then spraying it with a chemical weedkiller – far from ideal when close to watercourses or trying to protect native ecology.

Earlier this year, the Trust brought in local contractors to tackle stands of rhododendron and fuchsia. The latter has proved especially adept at colonising areas of clear fell sites where the Trust is looking to replace areas of former conifer plantations with native, broadleaved woodland.

Although attractive to look at when in flower, it is now widely recognised that these vigorous non-native plants shade out native species and, if left unchecked, can prevent the establishment of native woodland.

Whatever the plant species - be it prickly heath, rhododendron, or fuchsia - all require a significant amount of attention and investment over a lengthy period of time if they are to be controlled in a meaningful way.

We are in very early discussions with neighbouring landowners to hopefully begin a landscape-wide invasive species eradication programme around our Skye properties, beginning with Strathaird. Investigations are underway to find the most practical and efficient methods and our aim is to roll this work out in the winter of 2025.

• This excerpt from a longer article about INNS first appeared in the Autumn 2024 edition of the John Muir Trust Members' Journal. If you would like to receive our Journal twice a year please consider joining the Trust as a Member.

Photos courtesy of John MacRae (and Mac pictured above)