Foxtail barley, a persistent and often misunderstood grass, presents a significant challenge for agricultural producers and land managers across temperate regions. This hardy plant, scientifically known as Hordeum jubatum, combines aggressive reproductive strategies with a troubling toxicity that affects grazing animals. Understanding its lifecycle, identification features, and the risks it poses is essential for effective pasture management and animal safety.
Identification and Botanical Characteristics
Correct identification is the first step in managing this invasive species. Foxtail barley is a perennial grass that typically grows in dense clumps, reaching heights between 20 and 60 centimeters. The most distinctive feature is its head, which resembles a fox's tail, hence the common name. This head is a dense spike that contains spikelets covered in long, sharp awns. These awns are not merely cosmetic; they are equipped with tiny, backward-pointing barbs that facilitate seed dispersal by attaching to fur, clothing, and machinery. The leaves are usually rough to the touch and exhibit a grayish-green color, adding to its weedy appearance in cultivated fields.
Lifecycle and Propagation
The success of foxtail barley lies in its efficient lifecycle. It is a prolific seed producer, capable of generating thousands of seeds per plant each season. These seeds exhibit remarkable persistence in the soil seed bank, remaining viable for several years and germinating when soil conditions are favorable. Germination often occurs in the spring, but a secondary flush can happen in the fall, making it a difficult opponent in agricultural rotations. Because it completes its lifecycle quickly—from germination to seed production in a single season—it can easily outcompete desired forage crops for resources like water, sunlight, and nutrients.
Geographic Distribution and Habitat
While native to northern and western North America, foxtail barley has successfully naturalized in many parts of the world with similar climates. It thrives in disturbed soils, making it a common sight in overgrazed pastures, roadsides, and agricultural fields. It shows a particular tolerance for saline and sodic soils, where other desirable forage species might struggle or fail entirely. This adaptability allows it to colonize areas where other vegetation cannot, creating monocultures that degrade the quality of the land and reduce overall biodiversity.
Toxicity and Health Risks to Livestock
Dangers to Horses
The primary concern with foxtail barley is its toxicity to livestock, particularly horses. The sharp, barbed awns pose a direct physical threat, capable of causing severe mouth ulcers, gum infections, and damage to the digestive tract if ingested. More critically, the plant contains alkaloids that can lead to "chewing disease," or nigropallidal encephalomalacia. This neurological condition is often fatal and causes symptoms such as lip twitching, difficulty swallowing, and central nervous system depression. For horse owners, the presence of this grass in pastures or hay is a serious safety hazard that requires immediate removal.
Impact on Cattle and Other Animals
While generally less sensitive than horses, cattle and sheep are not without risk. The awns can still cause physical injury, leading to eye infections or abscesses in the mouths and digestive tracts of these animals. Ingestion of large quantities can cause digestive upset, reducing weight gain and milk production. The plant's ability to accumulate nitrates presents an additional danger, similar to other nitrate-prone weeds, potentially leading to poisoning in high-stress situations such as drought or rapid growth phases.
Management and Control Strategies
Effective control requires an integrated approach that combines cultural, mechanical, and chemical methods. Due to its persistent seed bank, relying on a single treatment is rarely successful. In pastures, promoting healthy, dense stands of desirable forage through proper fertilization and rotational grazing helps suppress germination. Mowing can be effective before seed head formation to prevent spread, but it does not eliminate the root system. For infested agricultural fields, selective herbicides applied at the correct growth stage can reduce populations, though repeated applications over several seasons are usually necessary to deplete the seed bank.
