Scientific Name: Epilobium obscurum
Perennial, speading by seed. Looks similar to other smaller willowherbs and occurs as frequently as Broad-leaved Willowherb, with the same type of flighted seed.
Easily uprooted and will not re-grow if the basal growing point is removed.
Herbicides to use:-
Dichlobenil prevents emergence of seedlings among established
woody plants, for up to one year.
Paraquat, Diquat kills top growth on contact, use at seedling stage.
Glyphosate, systemic action killing the whole plant, do not use when in flower as the seed may be produced before the plant is killed.
Follow these links for further details on Weeds, Weed
Removal and Weed