Starting to plan your garden for spring? Add removing invasive shrubs to your to-do list.
It is inevitable. The average homeowner is very likely to find invasive shrubs on their property at some point. These sneaky invaders seed rapidly, leaf out early, and can be difficult to treat once established. Recognizing and knowing how to remove these species is important to protect the health of our local environment, and conveniently, winter is one of the best times to remove them.
What is an invasive species?
The U.S. Department of Agriculture defines an invasive species as those species that are both non-native and cause (or are likely to cause) economic or environmental harm, or harm to human health. There are more than 40 plants considered invasive in the state of Illinois, with more added each year – meaning that the average homeowner has a lot of invaders to keep an eye out for. Not every invasive is created equal though, and some are more aggressive than others.
Meet the common culprits
Common buckthorn (Rhamnus cathartica), glossy buckthorn (Frangula alnus), and bush honeysuckle (Lonicera tatarica) are the most common invasive shrubs found in Illinois. In fact, according to the Chicago Region Trees Initiative, buckthorn is the most abundant tree in the greater Chicago region at about 27% to 28% of the region’s tree canopy. That figure includes private property. Compare that to the widely popular maple tree at only 13% abundance, and it is clear how pervasive buckthorn is in our landscape.
Buckthorn harms our local ecosystem by outcompeting the native species that are crucial to pollinators and stream and lake health; harming the health of the birds that snack on (and thus spread) their berries; and releasing a chemical into the soil that inhibits the growth of surrounding plants.
Learn control methods
Fall and winter are the best times to remove invasive shrubs like buckthorn and honeysuckle. Removal is most effective before their leaves set in early spring, and while they are conserving most of their energy in their roots. Herbicides such as glyphosate and triclopyr are commonly used when removing invasive buckthorn and honeysuckle and are usually encouraged to prevent the shrub from resprouting. Always read and follow label and safety instructions when applying herbicide.
You can treat the buckthorn and honeysuckle on your property by following the cut-stump method for larger plants, or just pulling small saplings. When pulling, make sure to remove the root crown so that the plant does not resprout. You can learn more about invasive shrubs and the methods to control them at extension.illinois.edu/forestry and extension.illinois.edu/invasives