The color and form of the flowers are the best ways to identify astragalus preussii; the lower, tubular portion (the calyx) is purple-red, while the upper petals are a much lighter pink purple, becoming bluish when dry. The uppermost petal (the banner) is wider than the others and arches upwards. The plant often forms large clusters containing hundreds of flowers. Leaves have the familiar pinnate arrangement, with 5 to 25 leaflets.