Toxic Parts:
cyanogenic glycosides
Flower Color:
  • flower color
waterside, meadows, haybales

Time of Greatest Risk


Geographical Distribution

Arrowgrass distribution - United States


Triglochin maritima

Seaside Arrowgrass, Shore Arrowgrass
7/ 10
Arrowgrass (Triglochin maritima) is a perennial, grass-like plant which is native to North America, South America, Europe and parts of Asia. Arrowgrass grows in shallow, brackish to freshwater marshes, road ditches, open wet prairies, tidal marshes, edges of wetlands and springs. Arrowgrass is of the Juncaginaceae plant family and starts growing in early spring.

Arrowgrass Toxic Components

Arrowgrass is more toxic when stressed or damaged due to frost, wilting, stunting or physical damage (mowing, chopping, etc). Plants lose their toxicity with drying. Highest concentrations of poison are in newly developing leaves and during and just after a drought. Arrowgrass growing under drought conditions has been found to be 5 to 10 times as toxic as those plants that have been partially submerged throughout the entire growing season. Death occurs within minutes of ingestion.

What Arrowgrass Looks Like

  • Flowers: 100+ short-stalked small, green flowers along a stout, naked stem in a narrow, spike-like raceme. Later the flowers turn into golden-brown fruits.
  • Leaves: Dark green, toothless, hairless, erect to ascending, mostly basal, blunt or pointed at the tip. When crushed, they produce a musky skunk-like odor (what cyanide smells like).
  • Stems: Flowering stems are smooth and often reddish to purple in color.
  • Fruit: Green to golden-brown, oblong, and divided into six evident carpels.