Flat Pea

Flat Pea

Lathyrus sylvestris

Photo credit: Bob Brett

Status in Squamish:


Status in Whistler:


Status in Pemberton:

Vectors of Spread:

Flat Vetchling, Narrow-leaved Pea, Wood Pea, Perennial Pea, Narrow-leaved Everlasting Peavine

ID Characteristics

Flowers: Tend to grow in clusters of 4 – 9 blooms and can be red, white, or pink. The petals have a distinct lateral, wing-like shape, with a single seed pod protruding from the center. The petals are two different sizes but the flowers are symmetrical (zygomorphic).

Stems: Are hairless, tendril-like strands of vegetation that are constantly climbing, growing approximately 1.8 – 2 m long.

Leaves: Narrow, smooth, ovate; this plant’s compound leaves boast a dark green-blue hue and grow in pairs along branched tendrils. The leaves are approximately 10 cm long and 2 – 3 cm across.

Fruit: Seed pods vaguely resemble edible peas, turning dark grey at maturity. The pods are long and fleshy, containing 10 – 20 small seeds each.

Roots: Establishing deep in the ground and under a broad horizontal scope, Flat Pea forms an especially dense root system. Reproducing primarily through rhizomes, this plant’s roots propagate extremely easily.

Similar Species
  • Native:

Photo courtesy of Walter Muma

Marsh Peavine: Found along mudflats and tidal marshes, lakesides and streambanks, this delicate Peavine is scattered across coastal B.C. Its flowers form stalked clusters of pink to bluish-purple blooms, and leaves are a broad, dark green.







  • Invasive:

Photo courtesy of Troy Evans, Great Smoky Mountains National Park, Bugwood.org

Broad-leaved Peavine: Found among dry thickets and roadsides, this non-native, invasive Peavine most commonly gets into the environment as an escaped garden ornamental. Its flowers cluster in groups of 4 – 9, with rose-tinged pink petals and pairs of leaflets growing out from the stems.

You can learn more about the similarities and differences of Broad-leaved Peavine and Flat Pea in this comparison factsheet.


Please report any sighting of Flat Pea by clicking here.

Habitat and Origin

Native to Europe, Flat Pea was a revered garden ornamental and useful erosion control tool. However, it lacks natural control methods in North America, and is considered invasive in BC.

This spindly vine thrives in full sun and dry, exposed soils. You might spot it creeping up and around shrubbery near roadsides, restoration sites, dry thickets, or logged cut blocks.

Current Distribution

Flat Pea Distribution in the SSISC Region in 2020 (data source: IAPP)

Propagation & Vectors of Spread

Capable of reproducing through both seeds and rhizomes, Flat Pea can be challenging to control. Its deep, well-established root system produces new growth every spring, while its seed pods, which contain 10 – 20 seeds each, twist off and eject the seeds up to 10m away from the parent plant.

Spreading most efficiently through human transportation, Flat Pea can be sold in “naturalized” garden seed mixes, brought into new areas through contaminated boots, tools, vehicles or clothing, and redistributed through regular, roadside mowing. Mother Nature also plays a role, though – its seeds and rhizomes are capable of spreading to new locations through waterways, birds, and other animals.

Ecological, Economic, & Health Impacts


  • Chokes out native plant life.
  • Forms dense, impenetrable monocultures.
  • Impacts groundcover species, shrubs, and trees.


  • Reduces land value.


  • Toxic to livestock and humans (can cause lathyrism if ingested).
  • Symptoms include muscle weakness, stiffness and loss of control.
What Can I Do?

Flat Pea is found in the Sea to Sky region, but with a limited distribution. The goal is to eradicate this species from the region, and to prevent new introductions.

Learn to identify Flat Pea: use the images presented in this profile page to learn how to identify Flat Pea.

What to do if you spot it: You can report any Flat Pea sighting by clicking here.



  • Regularly monitor properties for weed infestations.
  • Report any potential Flat Pea sightings to SSISC.
  • Ensure soil and gravel are uncontaminated before transport.
  • Check wildflower mixes to ensure that they do not contain Flat Pea.
  • Ensure that all plant parts are disposed of in a garbage bag if found in floral arrangements, land waste, or weed debris to prevent seeds from spreading.



  • Pick and collect Flat Pea blooms.
  • Mow over established Flat Pea infestations.
  • Unload, park or store equipment or vehicles in infested areas; remove plant material from any equipment, vehicles, or clothing used in such areas and wash equipment and vehicles at designated cleaning sites before leaving infested areas.
  • Plant Flat Pea in a garden, no matter how well-contained its enclosure may seem.
  • Move soil, land waste, or other weed debris that has been contaminated with Flat Pea.
  • Dispose of Flat Pea in the compost.




Hand-pulling has proven to be mildly effective and controlling the further growth of established Flat Pea populations. However, covering the weeds with a tightly fastened tarp, for at least 2 years, has proven to be highly effective – though, all other plant life caught under the tarp will also die off in the process.


Triclopyr, Dicamba, and Picloram have been effective at controlling Flat Pea infestations. Note, however, that Picloram is not suitable for wet, coastal soils.

We recommend that any herbicide application is carried out by a person holding a valid BC Pesticide Applicator Certificate. Before selecting and applying herbicides, you must review and follow herbicide labels and application rates; municipal, regional, provincial and federal laws and regulations; species-specific treatment recommendations, and site-specific goals and objectives.


Flat Pea has been found to be palatable and non-toxic to goats, which can be used for partial grazing control.