Weed of the Week #7: garlic mustard

Garlic mustard is a weed class A that is native to Europe, Asia and Northern Africa. It is not known to be toxic. This plant is on the Washington State quarantine list. Garlic mustard is a noxious weed because its vegetative growth starts early in the spring, outcompeting native and beneficial species that are still dormant. Its ability to reproduce high quantities of seed from a single plant can make it difficult to eradicate once it is well established. Seeds can survive several years in the seedbank, prolonging its ability to dominate a site.

This weed also changes the composition of a plant community by exuding chemicals that disrupt plant growth and certain plant mycorrhizal fungi connections, which are important for tree seedling health.

Flowers have four white petals. Seed pods are long and slender, curving upward, up to 2.4 inches long. The seeds are dark brown to black, grooved and oblong in shape. These plants can produce up to 8,000 seeds.

In Washington State, garlic mustard is found in forested understory areas including urban parks, on roadsides, trails, railroad tracks, streambanks, fields, slopes and flood plains. Garlic mustard reproduces by seed and is capable of cross pollination as well as self-pollination.

Hand pulling is an effective method of controlling this plant. Mature plants are easily pulled though care must be taken to remove all of the roots.

If you have questions about garlic mustard or any other noxious weeds and their identification and control, we can help. Please contact Andy Lea at 360-795-3852