Garlic mustard: Alliaria petiolata

Garlic mustard is a Class A noxious weed in Washington state and Grant County. Class A noxious weeds are non-native species whose distribution is still limited throughout the state. As you can imagine, preventing new infestations and eradicating existing infestations of Class A noxious weeds is a high priority at the state and local levels.

All Class A noxious weeds listed by the Washington State Weed Board are required to be included on county noxious weed lists. In addition, Class A noxious weeds are listed as prohibited plants by the Washington State Department of Agriculture. By law, these plants and their seeds cannot be sold in Washington.

Garlic mustard is a member of the Brassicaceae family of flowering plants. This family is commonly known as the mustards and includes cruciferous vegetables such as broccoli, cabbage, Brussels sprouts and kale.

A biennial to short-lived perennial, garlic mustard plants are garlic scented and can grow to a height of three feet. Flowers are white with four petals. Leaves at the base of the plant are rounded, while upper stem leaves are triangular shaped and alternate. Leaf margins are toothed with new leaves having an especially strong garlic odor. Reproduction is by seed, which germinates in early spring. Garlic mustard plants are capable of cross-pollination and self-pollination.

Garlic mustard is shade-tolerant and difficult to control once you have it. It will outcompete native vegetation and quickly becomes problematic in any area it invades. Garlic mustard will rapidly displace desired plants and should be properly identified and controlled in the early stages of infestation. It can easily be pulled by hand, but you have to be careful to remove all roots to prevent regrowth.

You may see garlic mustard while hiking in forested areas, as it can become established in the understory of a forest. You may also see garlic mustard growing in other areas such as roadsides, railroad tracks, streambanks and fields. Garlic mustard has been found in recent years in two eastern Washington counties, Grant and Okanogan.

If you suspect you have seen garlic mustard or any other noxious weed, please give us a call at the Noxious Weed Control Board of Grant County at (509) 754-2011, Ext 4710. We will be able to positively identify the plants and provide control recommendations. The Noxious Weed Control Board website is www.grantcountyweedboard.org.