Garlic Mustard Reprise
Garlic Mustard (Allaria petiolata) has been identified as a troublesome, aggressive woodland herbaceous weed that invades woodlands and outcompetes many native woodland wildflowers. First introduced from Europe in the 1800s for medicinal and culinary reasons, it now grows in dense stands in shaded natural areas where it is more tolerant of lower light levels. In addition to shading out native flora, Garlic Mustard serves up a double whammy; plants produce allelopathic chemicals in the soil that inhibit seed germination of other species. Each plant produces about 600 seeds; some reports estimate up to 7900 seeds/plant. These remain dormant in the soil for about 20 months so once an infestation gets started it takes time and attention over a period of time to be brought under control. The plant grows readily from seed.
Garlic Mustard is a biennial that flowers in the second year. First year plants produce 1-6 inch rosettes of bright green heart-shaped leaves. In the second season, the plant bolts to up to 4’ tall and produces flower clusters of white, four-petaled flowers in early spring. Dames Rocket, also an introduced woodland invasive weed blooms later in spring. These flowers also have four petals but bloom in colors of white, pink and lavender. When in doubt about identifying the plant, crush leaves or stems. All parts of the plant will produce a characteristic garlic fragrance. This weakens in the fall and may make identifying basal rosettes of first year plants more difficult to identify. In this case, evaluating the root of the plant and finding a slender taproot with a characteristic right-angled crook at the top of the root just below ground is characteristic.
Garlic Mustard should be removed in the spring before it flowers or in the fall when first year rosettes can be easily pulled. The Illinois Natural History Survey reference listed below includes several control methods. If you have Garlic Mustard in your woods, do nature and your woods a favor and work to eradicate this weed. Now, when soils are moist, is a great time to do some effective pulling, but pull from the base of the plant! The root will break off easily!