A relatively new weed that is
causing the disappearance of some native spring wildflowers and preventing the
emergence of tree seedlings has prompted Gov. Tommy G. Thompson to issue a
proclamation declaring May as Garlic Mustard Awareness Month. A relatively new weed that is
causing the disappearance of some native spring wildflowers and preventing the
emergence of tree seedlings has prompted Gov. Tommy G. Thompson to issue a
proclamation declaring May as Garlic Mustard Awareness Month.
Garlic mustard (Alliaria petiolata), an exotic European plant, is radically decreasing the biological diversity and beauty of the state's woodlands, says Kelly Kearns, a native plant specialist with the Department of Natural Resources Bureau of Endangered Resources.
The plant is a biennial, meaning that it has a
two-year life cycle. The first year it grows a few small inconspicuous low
growing leaves, which remain green in the winter. This allows garlic mustard to
begin growing early in the spring giving it an advantage over spring-blooming
wildflowers, which are quickly shaded out by the plant's second year growth.
By early May, the flowering shoot has grown up to
12 to 30 inches in height, and small white four-petaled flowers appear. In only
a few weeks, the flowers give way to long slender seed pods which produce small
black seeds. Garlic mustard is most easily recognized by the strong garlic-like
odor of the crushed leaves or stems, most noticeable in the spring or summer.
Plants that have flowers or seed pods should be
pulled along with the s-shaped root and disposed of by drying and burning,
burying or putting them in garbage bags. If composted, or thrown on the ground,
the seeds will develop and could infest new areas. Small non-flowering garlic
mustard plants can be pulled as well, but they will be harder to spot. Weed
trimmers often require a second treatment because roots left in the ground will
re-sprout. Fire is difficult to use as it often doesn’t kill all the garlic
mustard in an area.
Glyphosate herbicides, such as Round-up®, can be used in the early spring and/or late fall when garlic mustard is actively growing and native vegetation is dormant. These herbicides can be used in late spring once wildflowers have emerged but people should be careful to avoid spraying any native plants, Kearns says, and be sure to follow the label directions for the correct dilution. "People should plan on returning each spring to remove additional plants, as the seeds can remain viable for at least seven years," she says.
Milwaukee area residents may want to help with
the "Weed-Out" now in its fifth year, occurring on Saturday mornings
in May from 9 a.m. to noon at the following county parks: Doctor’s, Grant,
Kletzsch, Jacobus. Lake, Whitnall, Trimborn Farm, Menomonee River Parkway (just
north of North Ave.) and select Greendale parks throughout May and early June.
Contact the Weed-Out coordinator (262) 679-9943 for more information. Work
parties were held in Door and Dane Counties earlier in the month.
FOR MORE INFORMATION CONTACT: Kelly Kearns (608) 267-5066
From the Wisconsin DNR News & Outdoor Report, May 2, 2000
