Plant of the month: Golden Bean (Thermopsis rhombifolia)

Golden Bean (Thermopsis rhombifolia) is a legume found in the sand areas of prairies and in aspen forests where the water table is high. Native to North America, the Golden bean can be found throughout the southern parts of British Columbia, Alberta, and Manitoba and into Colorado and Nebraska. Within the Thermopsis genus, the only species present in Alberta is the Golden Bean. The genus name, Thermopsis, comes from Greek, meaning lupine to describe the flower’s resemblance to lupine flowers. The species name, rhombifolia, also comes from Greek, refers to the rhombic or diamond-shaped leaves. Growing in large patches, these stout plants have stalks covered in hairs. With leaves consisting of 3 leaflets, the flowers are a bright yellow and form clusters. As a member of the legume family, the flowers resemble that of the pea flower. The fruit is a greyish-brown, hairy, curved pod.

Blooming in early May through June, the Golden Bean is a source of nectar for butterflies, such as the Afranius duskywing and the Christina Sulphur. It is also used as a food source for the caterpillars of the duskywing and as a place for the Sulphur to lay its eggs. Not only does the Golden Bean provide nectar for butterflies, they also provide pollen for bees.

The Golden Bean has cultural significance to the Indigenous people. Also known by other names, such as the Buffalo Bean and wudzi-eh-ka, meaning buffalo-flower, by the Blackfoot, because these plants bloom in spring during the time that the buffalo leave their wintering grounds and into the prairies. When brewed as a tea, the Golden Bean has been used to treat stomach diseases in both humans and horses. It is also used as a yellow dye. Like all other legumes, the Golden Bean forms a partnership with bacteria in soil, where nitrogen from the air is incorporated into the soil for itself and the surrounding plants. The Golden Bean also forms a partnership with fungi that provides minerals to plant.

Similar to other early flowering plants, Golden Bean is extremely important for pollinators in the spring. You will see patches of Golden Bean in many parks and grassland areas right now in Calgary!

Posted on May 13, 2023 09:52 PM by jdo77