Information on Rosebay Willowherb

Common Name: Rosebay Willowherb
Scientific Name: Chamerion angustifolium
Irish Name: Lus na tine
Family Group: Onagraceae
Distribution: View Map (Courtesy of the BSBI)
Flowering Period


Click for list of all flowering by month
Rosebay Willowherb is not easily confused with other wild plants on this web site.


Also known asEpilobium angustifolium, this beautiful, tall, vigorous, showy perennial graces the margins of woodland, bogs, railway embankments and roadsides from June to September and can reach a height of almost 2 metres. It has slightly unequal, notched, four-petalled deep pinkish-purple flowers (15-25mm across) growing up a long spike. A hairy plant, it has oblong to lanceolate, coarsely toothed leaves. In autumn the downy seed pods split into four and releasing numerous long plumes of cottony hairs with tiny light seeds. This plant has become quite widespread across Ireland, possibly because it seems to thrive on disturbed land. This plant is native to part of the country and has been introduced to other areas. It belongs to the family Onagraceae.

I first identified this plant in Dalkey Quarry in 1975 and photographed it close to the Grand Canal at Vicarstown, Co Kildare in 2004.

If you are satisfied you have correctly identified this plant, please submit your sighting to the National Biodiversity Data Centre

Willowherb, Rosebay
Willowherb, Rosebay

Lus na Tine from whence its also sometimes known as Fireweed - colonises ground where there's been fire and is often seen growing on the hills after the gorse or heather have been burnt off.

Rosebay Willow-herb has been used in a few areas of medicine. The powdered root was said to stop internal bleeding and an infusion of its leaves is sometimes used to treat asthma.