Flat Peavine (Lathyrus sylvestis)

Flat Peavine, invasive plant

This is one species of 4 Lathyrus species known in BC. It is a perennial vine that can grow up to 7 feet long and climb using tendrils. The leaves are 3 inches long and 1 inch in width and are smooth. This species has light pink pea-like flowers in clusters of 5 to 15. It flowers between June and October. The seeds look like edible pea pods. It spreads primarily by roots. It can die back each winter and grow from the roots.


Habitat & Ecology

Peavine prefers dry soil and can tolerate partial to full sun. It thrives on disturbed sites and becomes dense especially along roadsides.


Peavine will become the main species along roadsides outcompeting all other vegetation. It will also climb shrubs and trees. The fruit and leaves contain a toxic amino acid that if ingested in large amounts can cause a disease called Laythyrism. It causes stiffness, weakness and no muscle control. Horses and humans are most susceptible as compared to ruminants like cattle or sheep.


Manual control like digging, mowing and cutting can be challenging for control because this species reproduces from underground roots. Mowing will likely spread the plants to new locations. Small infestations can be manually treated if all of the root matter is also removed. It is likely that several treatments of this kind will be necessary. Minimize soil disturbance and cover disturbed soil to minimize new growth of peavine. Please contact LRISS for all other treatment information.


Jefferson County Noxious Weed Control Program. Best Management Practices: Everlasting Peavine, Flat Pea. www.co.jefferson.wa.us/WeedBoard. 360-379-5610 ext 205.