Two-grooved milkvetch is a shrubby perennial native to the Mountain West, from Montana and western North Dakota down to northern Arizona and New Mexico. This hardy herbaceous plant thrives in Zones 3-6 and matures to 1-2.5 feet tall with an equal spread, displaying showy flowers from May through July. Its pinnately compound leaves and upright stems emerge from a branched, woody rootstock, creating a distinctive architectural presence in dry, sunny gardens. While it tolerates clay and dry soils with ease, this plant comes with an important caveat: it accumulates selenium in its tissues, making it unsuitable for consumption by livestock or humans.
Full Sun
Moderate
3-6
30in H x 30in W
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Low
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Two-grooved milkvetch grows where few other ornamentals thrive, thriving in the dry, alkaline, often selenium-rich soils where it naturally occurs across upland meadows and prairies. Its showy spring and early summer blooms attract butterflies and other pollinators while remaining untouched by deer, offering genuine wildlife value without the typical deer-browsing damage. The plant asks little once established, needing only full sun and moderate water to maintain its hardy, low-maintenance growth habit across a wide northern hardiness range.
Two-grooved milkvetch is grown primarily as a herbaceous ornamental plant, valued for its showy flowers and ecological role in supporting pollinator populations. In its native range, it historically served as a botanical indicator of selenium-rich soils, which livestock herders learned to recognize and avoid. Today, gardeners cultivate it in native plant gardens and xeric landscapes where its combination of beauty and extreme hardiness justifies its presence, though its edibility remains restricted due to selenium toxicity.
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“Astragalus bisulcatus evolved across the arid and semi-arid regions of the Mountain West, where it adapted to the challenging ecological conditions of upland meadows, prairies, grasslands, and roadsides. Its preference for selenium-rich soils reflects millions of years of specialization to environments where other plants struggle to survive. Native peoples and early settlers of the region encountered this plant in its natural habitat, though its toxic accumulation of selenium limited any culinary or medicinal applications. The plant's journey to cultivation reflects modern horticultural interest in native species and low-maintenance ornamentals suited to difficult growing conditions.”