Lotus corniculatus

Lotus corniculatus, “birdsfoot trefoil”
Fabaceae

Birdsfoot trefoil is probably best known as a perennial legume forage crop, but this species has also been used for reclaiming strip mine land and as a ground cover on paths with high foot traffic (Personal Communication).

Producing high-quality forage for cattle and sheep in soils with a low pH, poor drainage, poor native fertility, or fragipans prone to heaving can be difficult. Birdsfoot trefoil is a forage legume that is more tolerant of these adverse production conditions. It can reseed itself, is resistant to Phytophthora root rot and numerous alfalfa insects, responds well to fertilization, and does not cause bloat in animals. As a result, it is being grown more often in the northern United States and southern Canada, where production of other forage legumes is limited. In good growing conditions, alfalfa easily out-performs birdsfoot trefoil.

About 25 varieties of birdsfoot trefoil are currently available in the United States and Canada. Varieties are generally characterized by growth habit into two types, Empire and European. Both types are referred to as “broadleaf” trefoils. Empire-type birdsfoot trefoils are better adapted for grazing since they have fine stems, prostrate growth, and an indeterminate growth habit. European-type birdsfoot trefoils are better adapted for hay production since they are more erect, establish faster, and regrow faster after harvest. (Penn State Extension)

It is invasive in upper Midwest, forming dense mats choking and shading out most other vegetation and probably eventually reducing species richness (personal communication). It is most problematic in prairies and disturbed open areas, such as roadsides. Prescribed burns increase seed germination making it troublesome in native prairies (Minnesota DNR).

All parts of the plant are poisonous, containing cyanogenic glycosides (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. This species is polymorphic for cyanogenic glycosides. The flowers of some forms of the plant contain traces of prussic acid and so the plants can become mildly toxic when flowering. They are completely innocuous when dried. An orange-yellow dye can be obtained from the flowers. When ingested by humans in small quantities, the plant is supposed to act as an carminative, febrifuge, hypoglycaemic, restorative, vermifuge. The flowers are antispasmodic, cardiotonic and sedative. The root is carminative, febrifuge, restorative and tonic. The plant is used externally as a local anti-inflammatory compress in all cases of skin inflammation (Plants for a Future). Please see a competent clinical herbalist.