Common Name: Garlic Mustard
Scientific Name: Alliaria petiolata
Provincial Designation: Prohibited Noxious
Prohibited Noxious weeds are plant species designated in the Alberta Weed Control Act. Prohibited noxious weeds must be destroyed when found, meaning all growing parts need to be killed or the plant's reproductive mechanisms need to be rendered non-viable.
Garlic mustard is native to Europe and Asia and was introduced to North America as a medicinal and culinary herb.
Garlic mustard releases chemicals into the surrounding soil which can inhibit the optimal growth of native plants. It out-competes native understory species in forests which can lead to an overall loss of biodiversity. It also produces a toxin which hinders the growth of other plants.
Each of the cross-shaped white flowers has four petals and is 5-10 mm wide.
It is biennial. In the first year of growth, plants form clumps of round shaped, slightly wrinkled leaves. The next year plants flower in spring, producing flowers in dense clusters. As the flowering stems bloom they elongate into a spike-like shape.
The young leaves are dark in colour and range from heart to kidney-shaped. Mature leaves are characteristically heart-shaped, have toothed edges and are alternately arranged along the stem.
As the species name suggests, the leaves omit a garlicky odour when crushed.
This plant grows in moist woody areas and can reach up to 1.5 m tall.
Can Be Confused With ...
Shepherd’s Purse - Capsella bursa-pastoris - a nuisance weed, but the seed pods are triangular and stand above the stalk, rather than heart shaped and hanging below. The leaves are highly variable and the flowers look similar.
Stinkweed - Thlapsi arvense - a nuisance weed, which has a strong smell.
Native mustards - Brassica species - but all our native mustards are yellow, not white.
When in doubt, please send a picture through our 311 notifications or email firstname.lastname@example.org
Learn more about this species:
See Fact Sheet - Alberta Invasive Species Council