Beware the Garlic Mustard

Spring has arrived in Iowa City, and so have the weeds. Which means it's time to keep an eye out for Garlic Mustard. According to the Iowa DNR "Garlic Mustard is a rapidly spreading, highly invasive non-native plant. It was introduced from Europe in mid-1800s for medicinal and herbal uses and came to the U.S. without predatory beetles or other natural controls. Garlic Mustard threatens to rob Iowa of healthy, diverse native woodlands."  Unfortunately wildlife do not eat Garlic Mustard. Human intervention is the only way to control it.

Garlic Mustard is a woodland plant that favors shade or dappled shade, but it will also grow in sun given enough moisture.  The Iowa Wildlife Federation suggests that if you're out hiking in your favorite woods (or hunting for morel mushrooms) take along a big garbage bag and load it up with Garlic Mustard plants before they get a chance to set seed.  Garlic Mustard is not difficult to pull, especially if there has been recent rain. If you wiggle the plant a little then pull at a slight angle, you'll be less likely to break off the stem leaving the roots to re-sprout.

Garlic Mustard is a biennial - it flowers the second year.  The first year the plants stay short and has rounder toothed leaves.  It is often brighter green than its surroundings.

During its 2nd year, the plants spread into patches, and the leaves are more triangular/heart shaped. It gets up 12" tall  or taller.

By late spring, you'll be more likely to see Garlic Mustard patches in bloom.  Look for  heart shaped or triangular coarsly toothed leaves, with clusters of small 4-petal white flowers at the top of a 12" to 36" tall thin stalks.

The Iowa DNR has a great printable full color  Garlic Mustard brochure that contains color photographs of different ages of the plant, as well as suggested control techniques for small or large patches.  It's a handy thing to carry with you the first time you look for the plant.

In 2011 the Friends of Hickory Hill Park sponsored a Garlic Mustard Identification program with a naturalist from the Johnson County Conservation Department, and you can watch the video here.

There are also many websites that can help you identify Garlic Mustard. One of the best is the King County, Washington weed identification website.