Darrell Blackwelder: Liriope can be a weed

Published 12:00 am Saturday, April 20, 2024

Liriope, commonly known as monkey grass, is one of the most utilized landscape plant materials. Often integrated into landscapes as a border, redefining its use may create a new attitude for home landscapes, especially in shady areas under trees where grass refuses to grow. Mass plantings complete the landscape and flow easily under dense shady areas. Liriope should be mowed in late spring (now) after danger of a hard freeze has passed to rejuvenate growth and remove dead or winter damaged foliage. Set the mower at the highest level before mowing. Liriope grows quickly after the annual mowing with complete fertilizer to stimulate growth. This plant has few if any insect or disease pests and weeds have a difficult time competing with liriope.

However, because liriope grows well in shady areas, it can be a double-edged sword. The plant spreads very aggressively by runners. Liriope can grow below cement and come back up on the other side of sidewalks and driveways and integrate in other places in the landscape. If you have a small area of ground cover in your lawn or landscape, it’s best to dig it out immediately and remove the plant. But if you have large areas of the groundcover, the only method of control is to use a herbicide. To control the plant, use a product that contains glyphosate, the active ingredient in Round-Up. Be careful spraying glyphosate and other weed killers in your lawn. The herbicide is non-selective and will kill both the liriope and your desired grass or ornamental plantings. It will take several sprays to completely control this aggressive plant. Be patient.

Darrell Blackwelder is the retired horticulture agent and director with the North Carolina Cooperative Extension Service in Rowan County. Contact him at deblackw@ncsu.edu.