By Talie Leeb
There’s something creepy crawling neighborhood yards, and it’s not just costumed ghouls and goblins. Japanese knotwood (Fallopia japonica) has been spotted in some Beverly/Morgan Park yards. This invasive species spreads quickly, sometimes growing up to four feet in a week, choking out its competitor plants. Its fast-growing roots can grow through concrete and asphalt, destroying sidewalks, driveways and foundations.
Knotweed can be identified by its ruddy bamboo-like stems, pointed oval leaves and spikes of tiny white flowers that bloom in late summer. If left to its own devices a single Knotweed plant will send out shoots and spread across an entire yard and then into the neighbor’s property.
What should you do if you find knotweed in your yard? To start: DON’T MOW! Mowing over a knotweed clump will spread it further because it can reroot from cuttings that fall from the grass catcher.
After identifying a knotwood clump cut the stand down to the ground, treat with a glyphosate weed killer, and then cover the area with tarps (black plastic is best) and leave them there for as long as possible, retreating with weed killer and removing any new shoots as necessary. The entire process is long and laborious –– it can take months for the root system to fully die — but considering the disastrous effect on your home’s infrastructure, it’s well worth the effort.
For more information about identifying and controlling Japanese knotweed contact the U of I extension service: extension.llinois.edu
And if you think you have knotweed in your yard, we’d like to know. Call BAPA, 773-233-3100 or email TLeeb@bapa.org to report knotweed sightings in Beverly/Morgan Park.
