Perhaps it’s only fitting that during Illinois Invasive Species Awareness Month I would find one of the most pervasive plants invading our woodlands growing just down the very urban block where I live. Whether the several garlic mustard plants growing in a neighbor’s front yard were purposefully planted, I don’t know. They are pretty and their leaves make for a nice pesto.
But certainly the garlic mustard growing up out of cracks in the sidewalk are volunteers and indicative of just how aggressive this non-native species can be. Each plant can produce up to nearly 8,000 seeds, which, unchecked, will certainly spread to neighboring yards, down railroad corridors and into our local forest preserves.
So far this year, volunteers have helped protect our woodlands by removing 12,206 pounds of garlic mustard from several sites throughout northeastern Illinois, including Bluebell Woods at Midewin. (For updates and more information, go to the Northeast Illinois Invasive Plant Partnership http://www.phcwpma.org/GarlicMustard.cfm.)
Even if my neighbor purposefully planted some garlic mustard, like most people he was probably unaware that such plants are destroying what remains of our native woodlands, wetlands and grasslands.
Another neighbor boasts fine, manicured specimens of European buckthorn and Japanese honeysuckle. Every time I walk past his house, I can’t help but think of the hours I’ve spent hacking and chopping these highly aggressive non-native shrubs out of grassland bird habitat at Midewin.
Every October, another neighbor of mine ventures into some of the Calumet wetland areas and harvests armfuls of phragmytes, which overruns wetland areas even more so than garlic mustard does woodlands. He ties up the 10-foot stalks with feathery seed heads into something resembling bundled corn shocks and then displays them in his front yard along with Halloween decorations. At Midewin, this ill-considered import from Asia has escaped from roadside areas and established a toehold in the middle of South Patrol Road Prairie – the oldest and largest restoration area at Midewin.
Several Pullman neighbors have Japanese barberry bushes in their yards. Although not as aggressive as buckthorn and honeysuckle, they are showing up with increasing frequency in wooded areas at Midewin and elsewhere, courtesy of birds who feast on their berries and leave the seeds behind in their droppings.
Like many of my friends and neighbors in Pullman, I am equally proud of my garden (the subject of a profile in the current issue of Chicagoland Gardening Magazine, by the way.) In line with my love of wild nature, my garden boasts more than 40 different species of native prairie and woodland plants. However, I’ve got a few non-natives growing. Some roses. Clematis. Nothing that is an ecological threat. Or so I thought.
Turns out Eurasian lilies of the valley are proving a slow but steady threat to forest areas, as well as to my parkway where they are battling native anemone for dominance. I haven’t yet seen any at Midewin, but I’m not taking any chances. Out they’re coming this weekend.