Dakota native prairie ground plum, Astragalus crassicarpus, of hilltops and slopes.
…On higher ground they gathered long branching stems of purple buffalo bean pods. – By the Shores of Silver Lane, Chapter 8, “Silver Lake”
It’s late summer when Laura and Mary walk near Silver Lake and pick tiger lilies and buffalo bean pods. After mentioning buffalo beans in her Pioneer Girl memoir, Laura Ingalls Wilder couldn’t remember if she saw them in the early 1880s or if they were brought in later, so in February 1937, she wrote to tell daughter Rose that she was writing to her sister, Grace Ingalls Dow, to ask about prairie flowers.
When Grace’s reply came, although she listed a number of flowers that used to grow on the prairie, buffalo beans weren’t specifically mentioned. Grace did write: “There were two kinds of wild peas, blue and purple… and wild clover bean. There were tiger lilies in low places.”
Laura’s purple buffalo beans are Astragalus crassicarpus, also known as prairie ground plum or ground-plum milkvetch. The flowers are pea-shaped and grow in clusters on stalks up to four inches tall. The fruit ripens into reddish-purple pods that are less than an inch in size and resemble a plum, several on each stem. Click HERE to see a photo of the fruit (beans).
Wilder writes that she and Mary gathered buffalo beans on “high” ground; they grow best on poor-soil slopes or hilltops where they get maximum sun exposure. Flowers appear early in the spring, and by May or June, the fruits are large enough to eat. Each bean contains small black seeds which provide winter food to birds and rodents.
buffalo bean pods (SSL 8; PG)