The perennial grass Broomsedge (Andropogon virginicus) is a tenacious, warm-season species often found in disturbed areas and pastures with poor soil quality. This native plant is considered a noxious weed because it forms dense, inedible clumps that quickly outcompete desirable vegetation. Eradicating Broomsedge is difficult due to its dense, fibrous root system and prolific seed production, which is easily dispersed by wind. Successfully removing and preventing this weed requires an integrated management strategy combining physical, chemical, and long-term soil health actions.
Identifying Broomsedge and Understanding Its Growth Cycle
Confirming the presence of Broomsedge is the first step toward effective control, as this weed possesses distinct visual characteristics. The plant is a bunchgrass, meaning it grows in dense, upright tufts that can reach heights of 2 to 4 feet at maturity. While young plants are a dull bluish-green color, they undergo a transformation in the fall, turning a coppery-red or golden-orange hue that persists throughout the winter.
The leaves are relatively long and narrow, emerging from a basal crown with flattened, often hairy sheaths. Its fuzzy seed heads, covered with fine silky hairs, appear in late summer or early fall, leading to seed dispersal by late October. Broomsedge is a warm-season grass, initiating growth when soil temperatures consistently rise above 60°F. This growth pattern determines the optimal timing for chemical treatments aimed at long-term eradication.
Physical Removal and Mowing Strategies
For small, isolated patches or younger Broomsedge plants, physical removal is a practical method of control. Hand-pulling is most effective when the entire dense root crown can be extracted. The root system is fibrous and dense, but generally remains concentrated within the upper 3 to 4 inches of the soil profile.
Mowing strategies can weaken the plant and limit its spread, though they will not kill an established population. Frequent, low mowing is necessary to prevent the plant from producing its prolific, wind-dispersed seed heads. A successful approach involves clipping the plants twice during the growing season, typically in mid-July and again in early September. This repeated defoliation depletes the plant’s stored energy reserves, leading to a gradual reduction in the population over several years.
Chemical Control Options and Application Timing
Chemical intervention is often necessary for areas with widespread or mature Broomsedge infestations. The most effective herbicide for this perennial grass is a non-selective product, such as glyphosate. Since these products also destroy desirable plants, application must be highly targeted to avoid damaging surrounding turf or pasture species.
Selective application methods include spot treatment using a backpack sprayer or employing a rope wick applicator. The rope wick device allows the herbicide to be applied directly to the taller Broomsedge stems, preventing contact with lower-growing grasses. Timing the chemical application is the most important factor for success because it capitalizes on the plant’s physiology.
The optimal window occurs in late summer or early fall, after mid-July, when the plant is actively translocating resources down to its roots in preparation for winter dormancy. Applying the herbicide during this late-season translocation ensures the chemical is carried deep into the root crown, maximizing the systemic effect. Studies show that applications made after July 15 provide good to excellent control, while spring applications are significantly less effective. A single application may not be sufficient to eliminate large, established clumps, and a follow-up treatment the following year is often required. Safety precautions, including wearing personal protective equipment and minimizing wind drift, must be strictly followed.
Long-Term Control Through Soil Amendment
Broomsedge is recognized as an indicator plant, thriving in soils with low fertility and high acidity. It flourishes in conditions where the soil pH is below 5.5 and nutrient levels, particularly phosphorus, are deficient. Correcting these underlying soil issues is the most important step for achieving permanent Broomsedge control.
The process must begin with a comprehensive soil test to determine the pH level and nutrient requirements. For acidic soil, applying agricultural lime, which contains calcium carbonate, is necessary to raise the pH. Liming the soil creates an environment unfavorable to Broomsedge while simultaneously making nutrients more available to desired grasses.
Once the pH is addressed, a balanced fertilizer should be applied according to the soil test results, focusing on phosphorus and nitrogen. Research shows that the combination of lime and phosphorus fertilization provides the greatest reduction in Broomsedge populations. This strategy allows desirable grasses to become more vigorous and competitive, enabling them to outcompete and shade out Broomsedge seedlings. Improving the soil environment takes time, and significant population reduction may require several growing seasons to achieve.