"Beauty Gone Wild "

Why rhododendron is such a problem in Scotland’s temperate rainforests

Rhododendron ponticum is beautiful. It is also one of the biggest challenges facing many of Scotland’s temperate rainforests.

At Re-Inversnaid, rhododendron was planted as part of the Victorian ornamental garden around the Lodge. Over time it spread beyond the garden and into areas of native woodland.

The problem is not simply that it takes up space. Dense rhododendron creates heavy shade and makes it difficult for native plants to establish. Its leaves also create a layer of material on the ground that behaves very differently from much of the native vegetation around it.

That has become particularly clear through the work we have been doing here.

Getting Rid of It

There is nothing particularly glamorous about removing rhododendron.

It is physical, muddy work. The plants are cut and treated, and the branches and larger material are removed from the cleared areas.

But we have learned that removing the branches is only part of the job.

The leaf matter is important too. Rhododendron leaves have a thick cuticle and are acidic, so they take considerably longer to break down than much of the native leaf litter around them. Where this material was left on the ground, we did not see the regeneration we were hoping for.

As we cleared more areas, we began to physically remove the leaf matter as well.

What We Are Seeing

The difference has been significant.

The areas where we have removed the rhododendron, cleared the branches and physically cleared the leaf matter are the areas where we are seeing natural regeneration taking place.

Birch, Rowan, Oak and other native species are beginning to establish in these cleared areas. Where the rhododendron leaf matter has been left, we have not seen the same response.

It has changed how we approach the work.

What initially looked like a job of cutting back an invasive plant has become a more careful process of clearing the living plant, removing the material it leaves behind and then watching what happens next.

Learning as We Go

This is a good example of how our approach to rewilding is developing.

We don't have a fixed recipe for Re-Inversnaid. We make an intervention, watch what happens and adjust our approach when the evidence suggests we should.

In this case, we learned that cutting the rhododendron and removing the branches wasn't enough. Clearing the leaf matter was also important if we wanted to create the conditions for natural regeneration.

That doesn't mean the same approach will work in exactly the same way everywhere. Different parts of the site have different histories, soils, vegetation and conditions.

But each area we work on gives us another opportunity to learn.

The aim is to remove barriers to natural recovery, then give the landscape the best chance to do more of the work itself.

There is still plenty of rhododendron to tackle.

And plenty more to learn.