Alliaria petiolata (Garlic Mustard)

Michael's Opinion

A biennial invasive plant that is rapidly becoming a problem in woodland areas where it out-competes native flora. Purported to be alleopathic.

Botanical Information

SynonymsAlliaria officinalis
CategoryWildflowers & Weeds
OriginNative to northwestern Africa, western and central Asia, and Europe.


USDA Hardiness Zone1a - 6a
USDA Hardiness Ref.
Canadian Hardiness Zone0a - 5b
Canada Hardiness Ref.
RHS Hardiness ZoneH7
RHS Hardiness Ref.
Temperature (°C)-51 - (-21)
Temperature (°F)-60 - (-5)
Height30 - 100 cm
Flowering PeriodMay, June

Description and Growing Information

Notable SpecimensJoany’s Woods, West Williams, Middlesex County, Ontario, Canada.
Leaf DescriptionThe leaves are stalked, triangular to heart-shaped, 10-15 cm long (of which about half being the petiole) and 5-9 cm broad, with a coarsely toothed margin.
Flower DescriptionThe flowers are produced in spring and summer in button-like clusters. Each small flower has four white petals 4-8 mm long and 2-3 mm broad, arranged in a cross shape.
Fruit DescriptionThe fruit is an erect, slender, four-sided pod 4-5 cm long, called a silique, green maturing pale grey-brown, containing two rows of small shiny black seeds which are released when the pod splits open.