Garlic Mustard (Alliaria petiolata)

Garlic Mustard (Alliaria petiolata)

Garlic Mustard tolerates shade and grows in rich moist areas, which makes this plant of particular concern since it is commonly found invading woodlands. It can outcompete native flowering woodland plants like Sweet Cicely, Dutchman’s Breeches and violets. Fortunately, Garlic Mustard is not yet widespread on PEI. We hope to keep it that way!




Garlic Mustard was first recorded in the US in 1868 and in Canada in 1897 and was likely brought to North America as a food cultivar as it was traditionally used in Europe as a culinary and medicinal herb. Garlic mustard reproduces mainly by seed with one plant producing thousands of shiny black seeds that can spread several metres from the parent plant. In the case of long distance dispersal, seeds are moved about by animals and humans, and in some cases water.


Allaria petiolata is a member of the mustard family.

  • First year plants form leafy rosettes close to the ground
  • First year leaves are kidney-shaped with scalloped edges
  • Second year plants can reach 1m and have a flowering stalk
  • Flowers are small and white with 4 petals, and grow in clusters at the top of leafy stems
  • Second year leaves are arranged oppositely on stalks, coarsely toothed and are triangular to heart-shaped
  • Leaves give off a garlic or onion odour when crushed
  • Mature flowering (second year) plants can reach up to 3.5 feet
  • Very tolerant of shade and grows well under forest cover

PEIISC factsheet on Garlic Mustard

PEIISC factsheet on Managing Garlic Mustard

Garlic Mustard is considered a priority species for the PEI Invasive Species Spotters Network. If you see this plant, please report your sighting.