Garlic Mustard – Alliaria petiolata
Garlic mustard is an extremely invasive weed was found in Burns Bog in April 2016. This is only the second confirmed location of this plant in the Lower Mainland. Garlic mustard can quickly dominate forested areas because it produces many seeds and secretes chemicals into the soil that stunt other plants.
Delta is concerned that garlic mustard may be present elsewhere. Contact the Office of Climate Action & Environment if you suspect you have found garlic mustard. Early detection is critical to ensure control measures are rapidly deployed before the opportunity for complete eradication is lost. We need your help to prevent garlic mustard from infesting other areas of Delta! This weed is most prolific is shady areas, but can easily grow in sunnier locations as well.
Garlic mustard is a plant with a fixed two-year life cycle (biennial). In the first year, it is a low-growing shrub with rounded (kidney-shaped), wrinkled leaves that have a scalloped margin. Leaf size ranges from 2-10 cm in diameter. These leaves stay green throughout the winter.
In the second year, garlic mustard produces a single stalk starting in March. The leaves closer to the top of the stalk are triangular, but the leaves closer to the ground remain rounded. In April, at the very top of each stalk, a cluster of white flowers with four petals are produced.
By May, the flowers develop into long (5-8cm) and skinny seedpods that point upwards; the plant can be about 3-4 feet tall by this point. The seedpods dry out over the summer; the seeds mature and become black and are about 2-3mm long by 1mm wide. At the end of summer the parent plant dies but the dried pods crack open and the seeds disperse to start a new generation.
Garlic mustard gets its name from the garlic-like odor it emits when the leaves and stems are crushed. However, garlic mustard has some resemblance to stinging nettle, so it is not advised that you touch a suspected plant. As opposed to garlic mustard, nettle leaves are more jagged at the edge, are all triangular in shape, and are always growing in opposite pairs on the stem. Nettle stems and leaves have fine stinging hairs on them and the flowers grow in long clusters below the very top of the stalk. Nettle also does not produce the skinny seedpods.
More information on garlic mustard and other high priority invasive species can be found on British Columbia's Priority Invasive Species webpage.