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Chisago County Master Gardeners have been very active the past few weeks as we were at the Lindstrom Home Show, had our own Bonanza, and most recently were at the North Branch Community Connections Expo. Talking with gardeners I realized that the range is from those that have only room for a couple of potted tomato plants on their patio, to several acres. Among those several acres is a garden, trees, and in some cases undecided acreage. A growing concern with those untilled acres is it's a great place for unwanted, noxious, and invasive weeds, vines, and shrubs. Examples include Virginia Creeper, Buckthorn, and garlic mustard.

Garlic mustard is native to Europe and is now found in the northeastern and the Midwestern United States. It can be found in upland, floodplain, hardwood forests, along trails, roadsides, and rights-of-way. In other words, it can be found almost everywhere including your own backyard.

Introduced to this country in the 19th century as a cool season herb for its culinary and medicinal uses. It escaped cultivation and began invading wooded areas where it shades out native ground-layer plants. The first record of garlic mustard in Minnesota was in 1933 and has now spread throughout the state. It was placed on the noxious weed list in 1999.

The garlic mustard is a biennial seed that germinates early in the spring and grows close to the ground the first year resembling violets and creeping Charlie. The first year it could have been from three to eight kidney to heart-shapes leaves with the plant having a garlic smell. The second year the land could grow up to four feet tall. The flowers are white with four petals about one fourth inch in diameter, mostly clustered at the top of the stalk. The flower usually blooms in May.

The roots are slender and white with a crook just below the base of the stem, giving it an "S" shape. The seeds are small and black and enclosed in a long narrow pod. They mature in late spring or early summer and bust at maturity, spreading seeds six inches or more away from the plant. Seeds may germinate up to five years later and can mature even after the plant is cut down.

Hand-pulling is best for small plants and at least the upper half of the root must be removed to prevent resprouting. Cutting may also be effective as long as one cuts the flower stalk at soil level just as flowering begins. Cutting prior to flowering may promote resprouting.

Fall or early spring burning may be effective in fire tolerant habitats. Fire must be hot enough to consume leaf litter. Three to five years of burning followed by hand-pulling is needed for control.

Glyphosate is an effective chemical control when applied in late fall or early spring when other plants are dormant, as long as the garlic mustard is green and actively growing. Regardless of the method, monitor annually for at least five years, or until the seed bank is exhausted.

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