Lawn Maintenance for Johnson Grass

Identification

• Johnson grass is tall and coarse, growing in thick clumps or nearly solid stands. The grass can potentially reach a height of 8 feet and has stout rhizomes and smooth leaves that are dark green with white middle veins and a rusty color near the base. It typically grows on disturbed sites such as river banks and along roads.

Light Infestation

• If only a few plants are present, as is usually the case on high-quality sites, the usual maintenance method is to pull up individual plants. The best time to pull up the plants is in June after a rain, and be sure to remove the entire plant. Close mowing also helps fend off Johnson grass.

Heavy Infestation

• Pulling individual plants can be impractical with severe infestations, but close mowing can still be helpful, and tilling also is a possibility where practical. Herbicides may also be needed; The University of Illinois recommends spot treatment with 2 percent Roundup. Use herbicides only as directed on the container.