Blackwelder column: That's bluegrass in your lawn

Published 12:00 am Friday, April 3, 2009

Many people have questions about their lawns.
Warm weather and ample rainfall have cool season grass growing well. Unfortunately, weeds are also becoming a problem. Many are calling about weed control in lawns. Many of you may relate to the questions and situations posed to Extension during the past week.
Q: I have some type of grass coming up in my lawn that is short with a lot of seed heads. It comes up every year in my lawn and the edge of my flower beds. What is this grass and how do I control it?
A: The grassy weed is annual bluegrass, Poa anna. It is a winter annual that germinates in the fall, blooming profusely in the spring. There is really no practical method of control in the spring because it dies soon after bloom, as soon as warm weather arrives. Pre-emergence herbicides applied in the fall work well in shrub and flower beds.
Q: Is there a simple way to kill weeds in my lawn without buying a weed killer and fertilizer blend?
A: Yes, retail outlets sell broadleaf weed killer pre-mixed in a hose-on applicator. The weed killer is generally a combination of 2,4-D and other herbicides that are metered through the hose as the applicator rather than using a pump up sprayer. Apply the herbicide, wait 10 days, and spray again for maximum broadleaf weed control. I have used hose-on applicators with very good success.
Q: How do I kill wild onions in my yard?
A: The wild onions are most likely wild garlic. Most of the broadleaf lawn weed killers or Image will eliminate the weed. Herbicide applications 10 days apart usually give satisfactory results. Pre-measured hose-on weed control herbicides work well for those with small lawns.
Q: Is it too late to apply pre-emergence herbicides to lawns?
A: No, now is the time to apply pre-emergence herbicides, but don’t wait too long. The pre-emergence herbicide can be applied with fertilizer or as a stand-alone herbicide. However, as the soil warms, crabgrass and goosegrass germinates making pre-emergence herbicides useless. Generally, when the dogwoods are in full bloom, it is too late to apply pre-emergence herbicides for crabgrass.
Q: When can I kill bermuda grass?
A: Bermuda grass can be controlled when it is actively growing with glyphosate (Roundup and other generic products). There are also other products that will kill the weed. Bermuda grass is a warm weather grass, so active growth begins as early as May or June. Repeated applications will be necessary for complete control. The optimum time to kill bermuda grass is usually during the month of August.
Darrell Blackwelder is an agricultural agent in charge of horticulture with the North Carolina Cooperative Extension Service in Rowan County. Call 704-216-8970.