Terrestrial Invasives

Lythrum salicaria

Lythrum salicariaPurple loosestrife

Common Name 
Purple loosestrife
Legal Status 
Emerging Weed

A plant of European origin, it is an erect, hairy perennial that can reach up to 2m high. It has 30-50 stems and forms wide-topped crowns. The stems are reddish-purple or red to purple and square in cross-section and the downy leaves are lance-shaped. Showy spikes of rose-purple flowers appear in summer. The flowers are10-20mm in diameter, with six petals (occasionally five) and 12 stamens, clustered tightly in the axils of bracts or leaves. The fruit is a small 3-4mm capsule containing numerous minute seeds.

The flowers have passed, and the stalks will turn brown and persist through the winter.
Where does this species come from? 
The invasive Lythrum salicaria is native to Eurasia.
Why is it a problem? 
Under favorable conditions, purple loosestrife is able to rapidly establish and replace native vegetation with a dense, homogeneous stand that reduces local biodiversity, endangers rare species and provides little value to wildlife
Means of reproduction? 
Individual flowers have five to seven petals. A single mature plant can have 30-50 stems arising from one rootstock, and can produce an estimated two to three million seeds per year.