The Monday Garden
Garlic Mustard: The Invader's Edge
Issue No. 54 - April 6, 2003
by Sue Sweeney
The word ďAprilĒ comes from the Latin "aperire" meaning
"to open". In my zone, first come the trees,
lead by red maples and elms. Also ahead of the pack are invasives like the garlic mustard (Alliaria petiolata), growing
in a wooded lot near my grocery store.
Invasive critters, like the Asian Longhorn beetle and the Norway
rat, can sneak in the country but invasive plants need to entice
humans into importing them. In the case of garlic
mustard, early European immigrants valued this biennial member of
the mustard family because it tastes, well, like garlic.
Adding to its charm, itís high in vitamins A and C, and
easy to grow in moist part-shade. As an evergreen,
itís readily available in fresh form all winter, which was a
particularly good thing before supermarkets.
But being likable isnít enough. That just gets you into
the garden. To be invasive, you have to spread fast and beat
out the local competition by hogging the light, water, nutrients,
and space. Unfortunately, garlic mustardís chief competitors
include our beloved spring beauty, wild ginger, bloodroot,
Dutchman's breeches, hepatica, and trillium.
|Garlic mustard has infested 29 states and southern Ontario.
It does it by soaking up the rays all winter while the competition is
dormant under ground. It stays low (as pictured) through its first
winter, taking advantage of the insulating snow, warmth of the earth, and
winter sun. Then it shoots up 2í to 3í, with clusters with white
or pink cross-shaped flowers in May. By July, itís gone, leaving
only the upright, banana-shaped seed pods characteristic of the mustard
Curiously, the experts arenít sure how garlic mustard spreads.
They know you canít blame it on the birds or the wind. While
the plant makes thousands of seeds that remain viable for years, they fall
close to the parent. The white-tailed deer helps by clearing ground
that garlic mustard then can take over. But how does it move from
site to site? Best guess is animal traffic.
Getting rid of it: There are similar-flowered native plants, so first
check a crushed leaf for the garlicky smell. Then pull it up, making
sure to get all of the root, or keep it cut to the ground so it
canít flower. Herbicides and fire are also used (this is a cure?).
Whatever, keep it up for at least five years. Meanwhile donít put
the roots or seeds in the compost or garbage; place them in a black
plastic bag in the sun for several months to sterilize. (Since this
it what it takes to kill the stuff, you can see why garlic mustard is
Better idea: Successful invaders have fewer pests than the local
competition. Since humans are the most effective pests for
garlic mustard, The Brooklyn Botanic Garden suggests we start eating it
again. See the pesto recipe from The Wild Vegetarian Cookbook at
Caution: Never to eat plants grown near a road
or driveway. Heavy metals from car exhausts poison the ground and
end up in the plants for decades. Also beware of old industrial
sites, dumps and illegal dumping sites.