The Singletary Pea, also known as Caley Pea or Rough Pea, is a legume (Lathyrus hirsutus) utilized for decades as a hardy forage and cover crop across the Southern United States. The plant is recognized for its remarkable resilience, thriving where many other cultivated legumes fail to establish. Its use in agriculture stems from its ability to improve soil quality and provide nutrient-rich biomass. However, its widespread adoption is tempered by a significant concern: the plant carries a potential for toxicity.
Identity and Historical Significance
The Singletary Pea is an introduced, cool-season annual legume with a vining and semi-erect growth habit, typically reaching heights between one and three feet. Its compound leaves consist of two long, narrow leaflets ending in a coiled tendril, which the plant uses to cling to adjacent vegetation for support. It is identified by its small, pea-like flowers, which bloom in shades of pink, purple, or white, and its flat-sided, oblong seed pods covered in stiff hairs.
Originating in the Mediterranean region of Europe and Asia, Lathyrus hirsutus was introduced to the United States primarily for agricultural purposes. It gained particular prominence during difficult economic times in the Southeast, where its ability to grow on poor, heavy clay soils made it an invaluable, low-cost crop. The common name “Caley Pea” is credited to A.F. Caley, an Alabama farmer who championed the plant’s use in the region, solidifying its place in the agricultural history of the Southern US.
Cultivation Requirements
As a cool-season annual, the Singletary Pea is best planted in the fall or very early spring, allowing it to establish before the heat of summer. Fall planting (September to October) is preferred in milder climates, maximizing its benefits as a winter cover crop. Due to the tough outer shell of its seeds, scarification—lightly scratching the seed coat—is often recommended to encourage faster and more uniform germination.
The plant demonstrates adaptability, tolerating a wide variety of soil types, from well-draining loams to heavier, mildly acidic clay soils (pH 5.8 or higher). While it prefers full to partial sun exposure, its tolerance for less-than-ideal conditions is a major advantage. Once established, the Singletary Pea requires minimal intervention, needing little to no nitrogen fertilizer due to its natural nitrogen-fixing capabilities.
When sowing, seeds should be placed approximately a half-inch deep. For broadcast application in a forage setting, a seeding rate of 50 to 55 pounds per acre is common. Providing a support structure or planting alongside a small grain crop, like oats or rye, is beneficial, as its vining stems can reach up to 40 inches long. General care involves ensuring moderate moisture during establishment, but the plant is known for its drought resistance once mature.
Primary Uses and Applications
The primary agricultural value of the Singletary Pea lies in its capacity to serve as both high-quality forage and a soil-enriching cover crop. As a legume, it fixes atmospheric nitrogen, substantially improving soil fertility. This process provides an organic source of nitrogen for subsequent cash crops, a function often referred to as “green manure.”
Its vegetative matter is nutritious and utilized as hay or pasture for livestock, particularly cattle, offering a low bloat potential compared to other legumes. The dense growth makes it an excellent cool-season cover crop, stabilizing the soil, preventing erosion, and suppressing weed growth. The plant is also included in wildlife food plots, where its foliage is browsed by white-tailed deer and its seeds are consumed by upland game birds.
Understanding Toxicity Concerns
Despite its benefits, the Singletary Pea carries a risk of toxicity, known as Lathyrism, which occurs when the plant is consumed in large quantities. The toxic compounds are neurotoxins called lathyrogens, concentrated most heavily in the seeds and seed pods. Consumption of these lathyrogens can lead to neurological damage in animals, particularly non-ruminant species.
Horses are especially susceptible to neurotoxic effects, manifesting as incoordination of the hind legs, an unusual, wide-based stance, and exaggerated stepping, potentially leading to permanent paralysis. While cattle and sheep are generally more resistant, they can exhibit signs of hindlimb weakness and an inability to rise if they consume too many seeds. Consumption by pregnant cows may also lead to skeletal deformities in their calves.
To manage this risk, avoid grazing or harvesting the pea in late spring when seed pods have fully developed, as this is when toxin concentration is highest. If the forage is used, it must be properly cured and mixed with other feeds to dilute the concentration of toxic seeds. Toxicity is directly correlated with the quantity of seeds consumed, making management during the reproductive stage the most effective safety measure.