Johnson grass is a noxious weed in Illinois. The Illinois Noxious Weed law mandates that each landowner controls the spread of and/or eradicates this plant from their land. Johnson grass has rhizomes that grow horizontally underground and allow the plant to spread, as well as the ability to spread by seed. It commonly grows in riparian areas, disturbed sites, woodlands, and grasslands. It was introduced from Turkey as a foraging crop for livestock, but today it has been recorded as being present throughout most of the United States.
Johnson grass is regarded as a highly invasive species in many states and countries. It can survive in a wide variety of habitats, and it can grow up to 200 feet in rhizomes each year. These elements give it the ability to outcompete almost any plant population. Additionally, the plant produces prussic acid (hydrogen cyanide), which poses a health threat to livestock when eaten.
As an alternative, switchgrass (Panicum virgatum) is a hardy grass native to the United States. It is similar in appearance. There are a number of native and non-native species that could be used in place of Johnson grass. More desirable species may be found using the online Search Trees and Plants page of the Arboretum website. Before purchasing or planting, be sure to check for any local or state guidelines on this species, and ensure that this plant is suitable for its habitat by checking its attributes at mortonarb.org or plants.usda.gov.
- Family (English) Grass
- Family (botanic) Poaceae
- Tree or plant type Perennial, Grass
- Hardiness zones Zone 4, Zone 5 (Northern Illinois), Zone 6 (City of Chicago), Zone 7, Zone 8, Zone 9, Zone 10
