Rescue Grass (Bromus catharticus) is a cool-season grass common across North America. Although relatively short-lived, its vigorous growth during cooler months makes it a common invader of lawns, pastures, and disturbed soil. The name Rescue Grass originates from its historical value as winter forage, offering a green food source when other grasses are dormant. This dual nature means the plant is simultaneously appreciated by farmers for its quick growth and considered a nuisance weed by turf managers.
Physical Identification and Key Characteristics
Bromus catharticus is a tufted grass that grows upright, reaching about one meter in height and presenting a coarse texture. It forms dense bunches rather than spreading by creeping runners. Its leaves are noticeably broad, measuring up to 10 millimeters wide and sometimes 30 centimeters long. While the leaf blades are often hairless, the sheaths wrapping the stem frequently have a dense covering of fine, short hairs.
A distinct membranous ligule, a small flap of tissue where the leaf blade meets the sheath, is present and can measure up to four millimeters long. The most recognizable feature is the seed head, a large, openly branched panicle that typically nods or droops as it matures. These spikelets are large, flattened, and oblong, giving them an “oat-like” or “braided” appearance. Each spikelet contains multiple large florets, sometimes numbering up to twelve, which may be tipped with very short awns.
This flattened spikelet structure distinguishes Rescue Grass from other cool-season grasses, such as annual ryegrass. Annual ryegrass produces a slender, unbranched flower spike, while Rescue Grass spikelets hang from short branches in a looser arrangement. The fibrous root system supports its bunched growth habit.
Geographic Spread and Seasonal Growth Cycle
Rescue Grass is not native to North America; it originated in South America but has become widely naturalized across the globe. In the United States, it is most prevalent in the Southern and Western states. Classified as a cool-season annual or biennial, its life cycle aligns with the colder parts of the year.
The life cycle begins with seed germination in the fall when soil temperatures drop. Young plants establish themselves and grow slowly through the winter, remaining green when warm-season turfgrasses are dormant. Growth accelerates rapidly in early spring, allowing the plant to quickly dominate areas before summer heat begins.
This rapid spring growth is followed by the production of conspicuous seed heads. Once temperatures consistently rise in late spring and early summer, the plant completes its life cycle, turns yellow or brown, and dies off. This cool-season preference allows it to aggressively occupy space when desirable turf is weakest. The large quantity of seeds produced ensures the next generation will germinate the following fall.
Agricultural Roles and Control Measures
Despite its reputation as a weed, Rescue Grass holds a beneficial role in agriculture, primarily as a forage crop. Its ability to grow actively during the winter and early spring provides valuable feed for livestock when other pasture grasses are unavailable. This quick, cool-season growth also makes it useful for temporary erosion control on disturbed land during dormant months.
Managing Rescue Grass requires a strategy focused on preventing seed production and germination. Since it is a cool-season annual, the most effective chemical control is applying a pre-emergent herbicide in the fall, typically between late September and November. This application creates a chemical barrier in the soil, preventing seeds from successfully germinating.
If the grass has already germinated, a selective post-emergent herbicide can be applied during its active growth phase in late winter or early spring (January to early March). Cultural controls include mowing frequently to prevent the formation of mature seed heads in the spring. Restricting water in the late spring is advised, as watering the dying Rescue Grass encourages it to linger while warm-season turf establishes itself. For small infestations, young plants can be manually pulled before they produce seeds, ensuring the fibrous root system is completely removed.