Lysimachia terrestris is a herbaceous plant with opposite, simple leaves, and erect stems.

The flowers are produced in a raceme, 10–30 cm (4–12 in) long, at the top of the plant.

Late in the summer, reddish bulblets form in the leaf axils.

It is also found in the U.S. states of Oregon, Washington, and Idaho, and in British Columbia.

A major pest is Monostegia abdominalis, a sawfly whose larvae can completely skeletonize the leaves.