Lathyrus latifolius L.
Perennial pea is a long-lived erosion control plant that provides a low maintenance and attractive cover in highly erodible areas. It requires little input once established. Perennial pea is also useful as a wildlife cover plant. When planted with grasses and other legumes, it will inhibit the ability of other plants to invade the stand after it achieves full cover, and can be used to control woody plant encroachment of utility rights-of-way. Perennial pea can be overseeded on rip-rap to hide the bare rock.
This plant may become weedy or invasive in some regions or habitats and may displace desirable vegetation if not properly managed. Please consult with your local NRCS Field Office, Cooperative Extension Service office, or state natural resource or agriculture department regarding its status and use. Weed information is also available from the PLANTS Web site at plants.usda.gov.
Perennial pea is a rhizomatous, deep-rooted legume that climbs through the use of tendrils and can attain heights of 5-7 feet if support is available. When no support is nearby, the plant forms a viney mat 18-30 inches thick. In either case, a well established stand forms a dense mat of vegetation. The stems and petioles are winged with leaf-like appendages. The leaf consists of two long, narrow leaflets with parallel veins and bears the tendril from juncture of the leaflets. The flowers range from deep purple, to white or pink and bloom from mid-June to mid-August. The seeds produced are in 2.5-3.5 inch long seed pods that contain the hard round seed. Both the seed and the pod are black or dark gray at maturity. Perennial pea closely resembles sweetpea and flatpea. Perennial pea has about 8,000 seeds per pound.
Adaptation and Distribution
Perennial pea is adapted throughout the Northeast US and states around the Great Lakes on soils that are moderately well to well-drained. It grows best in full sunlight and is not well adapted to acid, droughty sites. Low fertility and acid soils can more successfully be stabilized with flatpea.
Perennial pea will not establish successfully unless the seed is incorporated into the soil. Broadcast and hydroseeding will not work unless subsequent erosion covers the seed, or a heavy mulch is applied. The best way to incorporate perennial pea seed on disturbed sites is to track it in with a bulldozer. Inoculated flatpea seed must be spring planted, or dormant planted in mid-fall. A drill can also used to plant the seed 1-1 1/2 inches deep. Perennial pea is always planted with a grass companion (typically tall fescue) to provide quick cover during the 2-3 year establishment period. With good agronomics on a good site, flatpea will cover the soil in 2 years. With poor methodology it may never be successful.
Lime is needed if the soil is below a pH of 5.0, and moderate levels of phosphorus and potash are beneficial. Coat the seed with the specific inoculant immediately prior to planting. Plant perennial pea at 20 pounds per acre(for a solid stand) with 15 pounds per acre of tall fescue or perennial ryegrass. To add some color to a grass planting, use 5 pounds per acre. More seed will not make up for lack of incorporation as outlined above.
None is required. Mow the stand no more than once per year, after full bloom, and no sooner than the third year after planting.
Cultivars, Improved, and Selected Materials (and area of origin)
‘Lancer’ (MI), the only cultivar commercially available, was jointly released by the Rose Lake, Michigan and Big Flats, New York Plant Materials Centers operated by USDA-NRCS. ‘Lancer’ is available in the seed trade.