Quack Grass
Quack grass is an undesirable, aggressive, perennial grass that grows as a weed in many lawns throughout the growing season. It forms in patches, and has a coarse fibrous root system, that spreads by long-lived rhizomes as well as by seeds.
Quack grass characteristics include auricles (ear shaped part) that clasp the stem, rhizomes, and a long, narrow spike for a seed head. The auricles of this weed helps to immediately distinguish it from most other grass weeds. Tall Fescue , annual Ryegrass , and perennial Ryegrass are similar grasses that also have auricles, but none of these grass weeds have rhizomes like quack grass. If not mowed, quack grass can grow to 4′ tall. Quack grass blades are flat, dull green to light blue-green, and taper to a point. The seed spike grows from 3″ – 8″ long and appears in July. Each quack grass plant produces about 25 seeds and they remain viable 3 – 5 years in the soil. Quack grass produces many unde
rground stems, called rhizomes, which are almost impossible to remove by digging. Broken pieces of rhizomes left in the soil will sprout to make more Quack grass plants. It takes 2 – 3 months for
a newly germinated plant to develop rhizomes. It is very important to eliminate the plants before they reach this stage. The creeping rhizomes are so tough they can push up through asphalt pavement. If left to grow, they will form a dense mat 4″ thick in the upper part of the soil. One plant can produce 300 feet of rhizomes each year. Never rototill where quack grass is growing. The rototiller will chop up the rhizomes and create thousands of new plants!
One
method of controlling Quack grass is to apply a non-selective herbicide that contains the active ingredient Glyphosate (Round Up). Be careful because Glyphosate kills desirable grasses as well as weeds. Apply the herbicide only on the Quack grass patches. One way to apply Glyphosate to help reduce damage to desirable grass is to mow the lawn , then wait 3-4 days, then wipe the Glyphosate onto the taller growing Quack grass with a paint brush, sponge mop, or applicator. Quack grass tends to grow quicker and taller than your desirable grasses therefore it will stand out a few days after mowing. Unfortunately there is no herbicide you can use that will not also kill the desirable lawn grasses.
Is there any chemical product that will kill the quack, but not the lawn?
Unfortunately the only product that will kill unwanted grasses is a non-selective herbicide such as “Round-up”. This obviously has to be used with care as it will kill all vegetation it comes in to contact with! One method you may try is putting the product on to a sponge. Try “painting” the blades of the unwanted grass with the damp sponge- again taking care not to drip excess product onto your desired grass. Once you eradicate the quack grass you will need to do corrective seeding as well to ensure other problem grasses or weeds do not take up home in the new weakened areas. Its a tedious process but with patience can work. Best of luck!