Castetter’s Milkvetch

Astragalus castetteri, commonly known as Castetter’s Milkvetch, is a perennial herbaceous plant belonging to the Fabaceae family. This species is native to the southwestern United States, particularly found in regions of New Mexico and Arizona, where it thrives in arid and semi-arid environments, often in sandy or rocky soils. The growth habit of Astragalus castetteri typically reaches heights of 30 to 60 centimeters, exhibiting a bushy form with multiple stems arising from a central crown. The plant often displays a spreading habit, allowing it to cover a larger area, which can be beneficial for soil stabilization.

The leaves of Castetter’s Milkvetch are pinnately compound, featuring numerous small leaflets that contribute to a feathery appearance. The flowers are distinctive, usually appearing in clusters, and are characterized by their typical papilionaceous shape, with colors ranging from pale yellow to purple. Blooming occurs primarily in the spring and summer months, attracting various pollinators, including bees. The fruit is a flattened legume pod that contains several seeds, which are dispersed upon maturation. This species plays an important ecological role in its native habitat by contributing to soil nitrogen levels through its symbiotic relationship with nitrogen-fixing bacteria, thus enhancing soil fertility. Additionally, it serves as a food source for wildlife and can be utilized in restoration projects to improve degraded landscapes. Adaptations such as deep root systems allow Astragalus castetteri to access moisture from deeper soil layers, making it well-suited to its arid environment.