Invasive Species – Himalayan Knotweed

Himalayan Knotweed (Persicaria Wallichii) is a robust rhizomatous perennial that can grow to 1.8 metres and produces loosely clustered pinkish or white flowers in late summer into early autumn.
Again, like the other Knotweeds this was introduced as an ornamental and has become very persistent in abandoned gardens and on roadsides or where there is garden waste. This Knotweed is often mistaken for Himalayan Balsam as it bears similar colour flowers as well as long lance-like leaves.
Himalayan knotweed is not as common in Ireland as the other knotweed species, although it is considered to be in expansive mode at present.