Q: I have regular grass growing in my numerous ornamental grass plants. Is there any way to remove the unwanted grass from these plants other than pulling it out, which is almost impossible?
— Jan Biasella, New Franklin
A: That’s a tough one, because the herbicides that will kill the invading turf grass will also kill the ornamental grass.
Greg Stack, a horticulture educator with the University of Illinois Extension, says you might be able to paint a broad-spectrum herbicide such as Roundup onto the weedy grass if you can get to it before the ornamental grass shows any major growth in spring, and if the weed grass is taller than the clump of ornamental grass. He suggests using a foam paintbrush to apply the weed killer to the unwanted grass without letting it touch the ornamental grass.
The University of Nebraska Extension says you can also prevent new weed grass plants from growing in your ornamental grass by treating with pre-emergent herbicide in spring. However, that will only keep weed seeds from germinating. It won’t do anything for the existing weeds.
Have a question about home maintenance, decorating or gardening? Akron Beacon Journal home writer Mary Beth Breckenridge will find answers for the queries that are chosen to appear in the paper. To submit a question, call her at 330-996-3756, or send email to mbrecken@thebeaconjournal.com. Be sure to include your full name, your town and your phone number or email address.