Alliaria petiolata  - garlic mustard

• An upright herb growing 1-3’
• The small, white, four-petalled flowers are only ¼ - 1/3” wide.
• The leaves along the upright stem are coarsely toothed
• The fruits are very slender pods, called siliques, and they stick upright from the stems.

Description

You can find Alliaria petiolata, garlic mustard, very early in the spring and throughout the year. This invasive, biennial species, usually taking two years to reach flowering and fruiting, begins in the fall as a rosette of leaves with scalloped edges. The rosettes stay over the winter, then an upright, leafy stalk grows in the spring. The leaves and particularly the roots have a garlicky odor when crushed. Flowers and fruits, producing a 100 or more seeds per plant, can from by late May. After the fruit is set, the plant slowly dies. Once the species is introduced to a location, it can quickly form a dense stand.

Ecological significance

From the Invasive Plant Atlas of New England website: Alliaria petiolata is successful in many types of habitats. It prefers moist, shaded areas, but can grow well at roadsides, edges of woods, along trails and in forest openings. Because of its shade tolerance it is one of few invasives that can be present and dominate a forest understory. Although most of the seeds fall in and around the existing population, the seeds can be transported by animals, humans, or vehicles, particularly where the seeds might stick in some mud that is transported in shoe or tire treads.

Garlic mustard is able to out-compete most other herbaceous plants for resources including water and space. As garlic mustard invades an area, other species diminish or are unable to become established. It has also been shown that garlic mustard impacts soil fungi that are essential for the germination and growth of many tree species. Garlic mustard is changing the character of New England woodlands.

Management options

Hand-pulling can be a very effective method for dealing with garlic mustard. The seeds of garlic mustard can last for several years in the soil. Depending on the size and age of the infestation, five or more years of diligence could be required to exhaust all the seeds in the soil. Hand-pulling all visible plants in mid-May and again in September or October will quickly diminish the population. Staff and volunteers of The Wild Flower Society visit the Plainfield Sanctuary yearly to hand-pull garlic mustard on that property.