Rescuegrass (Bromus catharticus) is a pervasive winter annual weed that quickly invades turfgrass lawns. This cool-season grass thrives during the dormant period of warm-season turf, allowing it to establish without competition. Effective control requires correctly identifying the plant and understanding its distinct life cycle to ensure proper timing for removal. Homeowners can successfully manage and eradicate infestations by combining cultural practices with strategically timed chemical treatments.
Understanding Rescuegrass Identification and Growth Cycle
Rescuegrass is classified as a winter annual, meaning its seeds germinate in the cool temperatures of late summer or early fall. The plants grow actively throughout the winter months, when most desirable lawn grasses are dormant or slow-growing, before producing seed in the spring. Once summer heat arrives, the mature plants die off, leaving behind a new generation of seeds ready to sprout the following fall.
Identifying rescuegrass requires looking for physical characteristics that differentiate it from desirable turfgrasses. The leaves are long, sometimes reaching over a foot, and can be sparsely hairy, particularly on the upper surface. The stems are flat or oval, and the plant grows in a tufted, erect manner. A defining feature is its seed head, which is an open, often drooping panicle with flattened spikelets that resemble small, compressed oats.
Manual and Cultural Removal Methods
For small, localized patches of the weed, manual removal is a practical and immediate solution. When hand-pulling rescuegrass, it is important to extract the entire root system to prevent any regrowth. This method is most successful when the plants are young and have not yet fully developed their root structures or set seed.
Cultural practices focus on creating a dense, healthy lawn environment that actively crowds out weeds. Maintaining a slightly taller mowing height encourages a thick canopy, which shades the soil surface and inhibits seed germination. Overseeding thin areas of the lawn with desirable turfgrass in the fall also increases competition for light and nutrients. Adjusting irrigation to avoid excessively wet conditions in the early fall helps reduce the favorable environment for seed germination.
Strategic Chemical Control
Chemical control is often the most effective strategy for managing widespread infestations, relying on a two-pronged approach: pre-emergent and post-emergent herbicides. Timing is crucial for success, as pre-emergent products prevent germination while post-emergent products kill existing plants.
Pre-Emergent Strategy
Pre-emergent herbicides must be applied before rescuegrass seeds begin to sprout in the soil. This application window occurs in late summer or early fall, around mid-September, when soil temperatures drop and conditions become favorable for germination. Common active ingredients include prodiamine and pendimethalin, which form a chemical barrier at the soil line to intercept developing seedlings. Because rescuegrass can continue to germinate throughout the winter, a second, lighter application may be necessary six to nine weeks after the initial treatment to maintain the protective barrier.
Post-Emergent Strategy
If rescuegrass plants have already emerged, a post-emergent herbicide is required to eliminate them. These products should be applied when the weed is actively growing, spanning from late fall through early spring, such as January to early March. Selective post-emergent herbicides, such as those containing ingredients like Celsius or Revolver, target grassy weeds without damaging the surrounding desirable turf. These chemicals are best applied when temperatures are cool and the plant is actively metabolizing the herbicide.
Preventing Future Infestations
Long-term success depends on maintaining a robust, healthy lawn that naturally resists weed intrusion. Proper cultural practices throughout the year are the foundation of this defense. Ensure your lawn receives routine fertilization based on a soil test to correct nutrient deficiencies or pH imbalances. Aerating the soil periodically helps relieve compaction, allowing for better water penetration and root growth in the desirable turf.