By Laura Phillips-Mao, PhD Candidate in Conservation Biology at the University of Minnesota and SAP resident
As you’re working in your yards this spring, keep an eye out for garlic mustard—a new invasive plant moving into the Saint Anthony Park neighborhood. Originally from Europe, garlic mustard is spreading rapidly through woodlands across much of North America. In addition to displacing native plants, garlic mustard changes woodland ecosystems by altering nutrient levels in soils and releasing chemicals that are toxic to beneficial soil fungi, resulting in reduced tree seedling growth. (seedling at right)
Garlic mustard is fairly common in the Twin Cities metro region, but has only recently been sighted in SAP. Wooded yards and parks are prime habitat for garlic mustard, so if left unchecked, garlic mustard will likely spread rapidly in our neighborhood—and large, dense populations of garlic mustard are extremely difficult to control (left).
Fortunately, garlic mustard is easy to control when it’s present in small numbers. The plants can be hand-pulled and composted with yard waste, provided they haven’t yet set seed. (Garlic mustard usually sets seed in late May/early June, and after this point, the seed pods should be sealed in a plastic bag and disposed of, so that the seeds don’t ripen and spread via compost.) The first-year plants can even be eaten! Young garlic mustard leaves make a tasty addition to salads and pesto, and the garlicky fragrance of crushed leaves can be a useful characteristic for identification.
First-year garlic mustard plants form a rosette of bright-green, scalloped, kidney-shaped leaves—similar to Creeping Charlie leaves, or a young violet (right). The rosettes over-winter green, and then bolt in the spring. Adult (second-year) garlic mustard plants grow 1-4 feet tall, with toothed, triangular leaves, and small (1 cm), white 4-petaled flowers (below) which later form long, skinny green seed pods called “siliques”, similar to those of the closely-related Dame’s Rocket (which has narrower leaves, and larger, more-colorful flowers). By July, the seed pods turn brown and pop open, scattering the seeds, and the adult plant dies.
For more information, or for help with identification, please contact Laura Phillips-Mao, PhD Candidate in Conservation Biology at the University of Minnesota, at (651) 324-7199 or contact us for her e-mail.
Useful websites for identification and control: http://www.dnr.state.mn.us/invasives/terrestrialplants/herbaceous/garlic...
http://www.eminnetonka.com/public_works/natural_resources/restoration/do...
