How Can I Control Invasive Garlic Mustard?

Is the garlic mustard well established in your garden or landscape?

Do you want to control invasive garlic mustard by mechanical cutting?

Do you want to control invasive garlic mustard with herbicides?

Cutting flowering plants at ground level by hand or with a string trimmer or lawnmower will kill a high percentage of garlic mustard plants. The lower the cut, the more effectively the plant will be killed. If the plants are flowering, it is important to remove all cut stems since seed development will continue even if the stem is severed from the root. Because mechanical cutting does not remove the root crown, it may be necessary to cut multiple times in a season to prevent seeds from developing on secondary stems that sprout from the rootstock. It will also be necessary to cut for many consecutive years until the seed bank is exhausted.

Several herbicides have a role in garlic mustard management. Herbicides should only be applied according to their label directions and using the protective equipment specified. Use of application equipment that can direct the herbicide to the target plant and reduce overspray or drift onto non-target plants is required. If other plants are killed, garlic mustard will likely replace them. Application of 1-2% glyphosate provides effective control of garlic mustard seedlings and rosettes. Bentazon applied at 8 ounces per acre is less effective on garlic mustard but with reduced risk to non-targets particularly annual and perennial types of grass.

Professional land managers trained in the use of prescribed fire may also consider burning for control of medium to large infestations of garlic mustard. The effectiveness of fire differs based on site characteristics and management goals. Most research shows that dormant season fires (March) are ineffective in garlic mustard control and that growing season fires (May) suppress garlic mustard but also adversely affect native understory forbs. Carefully timed spring fires (after garlic mustard emergence but before the emergence of desirable plants) may be effective.

Where garlic mustard is not well established, efforts should focus on detecting and eradicating new satellite infestations before a seed bank develops (i.e. dormant seeds in the soil). Pulling individual garlic mustard plants by hand is the simplest and most effective approach to managing small or isolated infestations. When pulling plants, it is important to remove the upper portion of the roots as well as the stem, since buds in the root crown can produce additional stems. All pulled plants should be removed from the site as seed ripening continues even after plants are pulled. Repeatedly hand pulling of garlic mustard is reported to be effective for control in small areas but has limitations.