End of the rhodi for £15m public enemy

However, one of the country's biggest landowners yesterday declared all-out war to wipe rhododendron from the map - because it kills everything in its path.

Forestry Commission Scotland (FCS) has embarked on an ambitious 15 million programme to eradicate the plant from its land over the next 15 years.

However, there was scepticism about whether the Scottish Government directorate would achieve its target, which follows campaigns against the alien invader that stretch back decades.

FCS native woodland ecologist Richard Thompson said: "Rhododendron ponticum is one of Scotland's most unwelcome invasive species - and it's just really nasty stuff.

"It suffocates habitats, hampers biodiversity and - if that wasn't bad enough - it harbours tree-killing phytophthora (bacteria] species.

"It looks nice to those who do not appreciate what it's like underneath the darn stuff. Getting rid of it would be a real shot in the arm for Scotland's environment and for forestry."

FCS said there are almost 16,000 acres of rhododendron on its land - nearly the size of Dundee.

The worst affected areas are Lochaber, with almost 6,500 acres, the Cowal peninsula, west of Dunoon, with 3,200 acres, and mid western Argyll, around Lochgilphead, with almost 3,000.

Mr Thompson explained that the extremely dense shade created by the plant killed off anything beneath it, and eventually entire woodlands by turning the soil acidic.

Most at risk are liverworts and lichens, which are very vulnerable to changes in light and humidity levels. Mr Thompson said: "It is having a terrible effect on these rare species."

FCS decided to act in response to a Scottish Government drive to eradicate non-native species, which also include crayfish and Japanese knotweed.

A spokesman said: "As the industry leader, we want to show that the national forest estate is no place for invasive rhodi."

A 1.6m first phase of the work is under way in Cowal, the Trossachs, Lochaber, west Argyll, North Highland and Galloway.

Among landowners to have embarked on rhododendron eradication programmes is the National Trust for Scotland, such as on 25 acres at Balmacara, near Kyle of Lochalsh.

It uses a variety of methods, such as injecting stems with chemicals. Another involves levering stems from their roots and using the rest of the plant as mulch to stop its seeds growing.

A spokeswoman said: "Early results show this approach has been very successful."

However, Scottish Land & Estates, the former Scottish Landowners Federation, sounded a note of caution.

Policy officer Janice Fenny said: "This is a huge but certainly welcome undertaking by FCS.

"It remains to be seen whether 15 years will be enough time to eradicate what is essentially a prolific weed which grows strongly in many parts of Scotland, including our members' land.

"Indeed, it will be impossible to clear the national forest estate if control work is not also carried out on private land as the species will simply spread back.

"Therefore, partnership working between the public and private sectors will be vitally important to the success of the project."

FCS's planning and environment manager Moira Baptie agreed on the scale of the challenge.

"We're under no illusions - it's going to be a big job, and while it sounds like it might be an expensive job, in terms of biodiversity it's a small investment for a big return," she said.

THORNS IN A GARDENER'S SIDE

Other examples of troublesome plants include Japanese Knotweed, which is so invasive it costs 150 million a year to tackle.

Plans were approved last year to release tiny bugs from Japan that feed on the plant. Another is sea buckthorn, a thorny-branched, silvery-leafed plant, sometimes nicknamed 'baked-bean bush' as it produces bright orange berries in the autumn.

Himalayan balsam, also known as policeman's helmet due to the shape of its flower, became invasive after escaping from gardens with its explosive seed dispersal and colonising of Scotland's river banks.