Current status: Answered by Christina McKelvie on 22 August 2023
To ask the Scottish Government what assessment it has made of the self-sown invasive buddleia (buddleja davidii) shrub on Scotland's forests, natural habitats and riparian areas and reports of its damage to the built environment, especially historic brick and stone buildings with lime mortar joints.
The Scottish Government has not carried out work to assess the impacts of buddleia on Scotland’s forests, natural habitats and riparian areas. Due to the preference of the species for disturbed open ground, its impact on these areas appears to be low. It is not considered to be forest-invasive at this time, and as such, currently poses limited concerns for woodland management or creation. We will continue to record and monitor its presence in the habitat restoration plans we will produce as part of our work to restore Scotland’s Atlantic rainforest.
We understand that buddleia is only likely to establish in buildings where there is a lack of building maintenance. Investing in overall repair and maintenance, therefore, will reduce problems caused by buddleia. Historic Environment Scotland has produced guidance, on both building maintenance and on the effect of biological growth on masonry, which is freely available on its website.