Binomial Name: (Elymus repens)
Quackgrass is a perennial narrow-leaf weed in the family" Poaceae”, and the Genus “Elymus”. Poaceae is also called Gramineae and it is the family of almost all grasses that grow as turf in a majority of the lawns around the world. Poaceae also includes bamboo, cereal grasses, and grasses that grow naturally in the pastures and grasslands. Quackgrass usually flowers from the mid-summer to late summer depending on the climatic conditions in different states of the US. It grows aggressively on sandy to clay loam soil in irrigated landscape from sea level to over 5900 feet or in the areas receiving nearly 20 inches of rainfall annually. Its presence along ditches, watercourses, turfgrasses, and agricultural soils is common throughout the US.
Origin and Distribution
Quackgrass is a B-category noxious weed in some parts of the US including, California, while it originated from Western Asia, Europe, northwest Africa, and the Arctic biomes. It was brought to the trivial northern climates for erosion control and an alternate forage for the livestock. It also reached into the US as a cereal grains contaminant and now extending its footprint in the turfgrasses and ornamental landscapes. Being an aggressive invader and a big competitor of the crop fields, it infests more than 37 crop species besides contaminating cereal grains in northern and coastal regions of the US. Quackgrass grows frequently in moist paddocks and disturbed lands whereas, its prevalence in mountainous meadows is most dominant where it thrives in a variety of land types.
Quackgrass-Identification
A mature Quackgrass plant remains erect and grows up to 4 feet in height forming clumps. The stem is round, and the nodes are swollen. The leaves are usually flat with a leaf width up to 5 inches and the length sometimes approaching up to 12 inches. The leaves may have some constrictions at the tips. The upper sides of the leaves may have a waxy coating, or they might be hairy whereas, the lower sides of the leaves have a waxy coating. Quackgrass flowers from late spring to early autumn. The flower head forms a spike measuring between 3 to 8 inches in length. The spikelet hence produced are stalkless and flattened, which, are arranged alternately to each other. The same spikelet contains seeds that disperse on maturity.
Quackgrass-Propagation and Lifecycle
Quackgrass adopts two different modes of reproduction and propagation: through seeds and underground creeping stems called rhizomes. Rhizomes are capable of piercing into compact soils and, that's the reason for their pervasiveness in disturbed soils. Even if the Quackgrass debris is not eliminated from the planting soil, it could spread to the neighboring fields. The rhizomes usually occur in the top 6 inches of cultivated land and may penetrate as deep as 8 inches. However, the lateral spread is up to 5 feet. Propagation through seed takes place with wind and the dispersals caused by the birds and livestock. Quackgrass comes into an aggressive growing mood when it crosses the 4 to 5 leaf stage, and all prevention strategies go well before this stage.
Fun Facts About Quackgrass
Quackgrass- Prevention and Control
Cultural Control
The best cultural control lies in masking the presence of Quackgrass for longer that helps in eliminating them from the turfgrasses permanently. This approach involves increasing the nitrogenous fertilizer dose besides increasing its absorption ratio in the turfgrasses and practicing repeated mowing. This approach will increase the vigor of the turfgrasses, and Quackgrass will not be in a position to compete. A vigorously growing turfgrass would suppress the Quackgrass growth and eliminate it in the long run. Usually, ½ pound of nitrogen applied biweekly over an area of 1000 square feet would help. Watering and fertilizing together could become more productive and result-oriented. Limiting any of the inputs could affect Quackgrass growth adversely. Physical removal of Quackgrass from the patches is somehow a difficult task and may not help control infestations due to the presence of a large number of rhizomes underground. Solarization is also helpful which, utilizes lying down a plastic film over the bad patches where Quackgrass grows extensively. It stops the growth beneath the plastic film, and reseeding could help if the surface comes out dry.
Chemical Control
Control using Pre-Emergent Herbicide
A non-selective herbicide could potentially help to kill already actively growing Quackgrass patches in the turfgrasses but, such application will kill turf grasses as well due to non-selective behavior. This practice will highlight the bad patches and kill them which require reseeding after you finish already growing turfgrasses with the Quackgrass as well. A non-selective herbicide would also need a repeated application by observing 13 to 14 days intervals. Reseeding can be initiated after 7-days of the second application.
Roundup Weed & Grass Killer Concentrate Plus
This concentrate contains 18% Glyphosate and 0.73% Diquat Dibromide in ready-to-use chemistry. This formulation actively kills everything green that comes into its direct contact. Nontarget vegetation can be shielded or covered with a polythene sheet. It starts killing Quackgrass and other targeted weeds within 24 hours of its application.
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The one-quart bottle can be used over an area of 3000 square feet of turfgrasses or applied as a spot treatment.
Roundup Quick Pro
Similar product chemistry like Roundup Weed and Grass Killer but different formulation type and ingredients ratio. Glyphosate 73.3% and Diquat Dibromide 2.9% is available in Granular form. It's a more powerful and active killer than Roundup Weed and Grass Killer. One sachet is mixed in 1 gallon of water to target Quackgrass in turfgrasses avoiding the desired vegetation. It’s also a non-selective herbicide and kills almost every type of turfgrass and vegetation.
- Glyphosate 73.3%, Diquat 2.9%
- Roundup QuickPro Herbicide is for use anywhere there is undesirable vegetation. Extra care should be taken to ensure that non-target vegetation is protected from any drift.
- The mix rate for Roundup QuikPro is 1.5 ounces per gallon of water.
Control using Post-Emergent Selective Herbicide
Controlling Quackgrass using a Post-Emergent herbicide is almost impossible as the Quackgrass and turfgrasses belong to the same species of plants, and a minor herbicide dose fluctuation can kill them both. A few herbicides somehow stress Quackgrass when applied in turfgrasses but, the control is not sustainable. Other herbicides may stress Quackgrass, and it starts growing again.
Learn How to control and get rid of other weeds in our complete Yard Weeding Guide.