WHITE BUTTERBUR : Petasites albus
Fortunately this is limited to some estates having been introduced by early collectors much as any other problematic plant. Its native origins are the mountains of central Europe and the Caucasus.
Some confuse it with rhubarb which is substantially larger and spikey. That is also usually confined to parks and gardens.
Common Butterbur being a native species is not a problem here. See index.asp?pageid=737871
The invasive white butterbur species differs from the common butterbur. It appears as flowers early in the year (Feb - May) with leaves appearing after flowering. These spiked white flower heads dominate damp riverside areas. The plants leaves are small when the plants are flowering, but later they become much larger, up to 30cm across. They resemble rhubarb leaves, but slightly more heart-shaped and grow low, forming dense carpets completely dominating the ground. [Wiki]
Butterbur has a rhizome root, so spreads readily in damp ground along rivers and road verges. It can regenerate from fragments of rhizome, which can be carried along river corridors by the water. It has invaded many areas of disturbed flood-prone ground. [Wiki]
SCOTTISH INVASIVE SPECIES INITIATIVE website : https://www.invasivespecies.scot/white-butterbur
SCOTLANDS NATURE website : https://scotlandsnature.wordpress.com/2020/05/08/buttery-business-the-challenge-of-the-invasive-white-butterbur/
