Below are brief description of the types of invasive knotweeds found in Ireland, and the differences betweed them. More detailed information that can be used for identifying can be found here
Japanese knotweed (Fallopia japonica)
Bohemian knotweed (Fallopia x bohemica)
Giant Knotweed(Fallopia sachalinensis)
Himalayan knotweed (Persicaria wallichii)
- often mistaken for Himalayan balsam as it bears similar colour flowers and also has long lance-like leaves.
- leaf edge is not as serrated as Himalayan balsam and its stems are bamboo-like, similar to other knotweeds
- Flowers can range in colour from white to pink and are loosely clustered.
- Like other knotweeds it can spread vegetatively from cuttings and fragments.
- Not as common in Ireland as the other knotweed species, although it is considered to be in expansive mode at present.