Epilobium ciliatum is a clumping perennial plant in the Onagraceae family, producing oppositely-arranged, oval to lance-shaped, toothed leaves. Flowers measure approximately 1cm across, they are purple-pink in colour and have deeply notched petals. This plant is covered in fine hairs, creating a fringed effect, hence this plant is commonly known by the name Fringed Willowherb, amongst others. Originating from North America, this species was introduced by accident to Europe, Australia and New Zealand, where its distribution is now expanding. It has a short life cycle, in favourable conditions it may produce a new seed generation within 10 weeks. It has been described as aggressive and has the potential to become a noxious weed, especially on agricultural land.