Wildflowers, Plants and Ferns, Pacific Northwest
The Birdsfoot Trefoil Plant is a herbaceous perennial. It has a well developed tap root with side roots near the soil surface. It grows erect up to a height of 90 cm. The stems are slender, branch well, and are moderately leafy. Leaves are smooth and consist of 5 leaflets. The bloom is made up of a cluster of bright yellow flowers arranged in a group at the end of the stems. When ripe, the brown seed pods extend outward from the stalk and look like a bird’s foot. The plant remains green and succulent during and after seed ripening.
Birdsfoot trefoil is a choice food for many birds and animals. As ground cover, it provides green cover most of the year and blooms profusely.
All parts of the plant are poisonous, containing hydrogen cyanide. In small quantities, hydrogen cyanide has been shown to stimulate respiration and improve digestion, it is also claimed to be of benefit in the treatment of cancer. In excess, however, it can cause respiratory failure and even death. The flowers of some forms of the plant contain traces of prussic acid and so the plants can become mildly toxic when flowering.