Lotus corniculatus / birds-foot trefoil
- roadsides and other disturbed areas
- numerous bright yellow, pea-like flowers
- three, oval and pointed leaflets
- seed pods are arranged like toes on a bird’s foot
Also known as: eggs and bacon, bird’s foot deervetch
Bird’s foot trefoil is a perennial herbaceous plant that looks like some clovers. It grows up to 2 feet tall with occasionally branching. It is typically sprawling and basically reaches whatever height its neighbors will physically support.
The inflorescences of bird’s foot trefoil are umbels of 3–12 pea-like yellow flowers. They have long stalks (peduncles) arising from leaf axils. The individual flowers are only about 1/2 inch across but are so visible that I have called them “small” rather than “teeny”. Each flower has five petals in a standard legume way, i.e. a standard (the biggest, sometimes called a banner), wings (smaller and slightly to the side), and a keel (a single, central petal at the bottom). The keel is not all that visible in the gallery photos. For an overview of this structure, but not focussed on this species, see here.
Despite the “trefoil” name, the leaves of this species have five leaflets. At least the central three are most conspicuous; the other two are at the base of the leaf where it joins the stem (no petioles) and look more like stipules. The three leaflets look somewhat like a three-leaf clover. Somewhat.
The flowers develop into small pea-like pods, and the common name comes from the appearance of those pods while still on the plants.
Bird’s foot trefoil is often planted as forage and has several advantages in this role. First, it is nonbloating, and only mildly cyanogenic. Second, it can survive fairly close grazing, trampling, and mowing.
It has also been used along roadsides for erosion control. On the plus side, its root system probably adds nitrogen to the soil because it is a legume and nitrogen fixer. On the down side, it can out-compete many native plants and has thus become a terrible pest. Indeed, it is now is so ubiquitous that it is beyond control. And it still appears in turf seed mixes as well as fodder mixes.
Given all this, it should be no surprise that bird’s foot trefoil can be found in a variety of highly disturbed habitats, like abandoned fields, roadsides and wastelands. Beyond that, it likes sun and will grow wherever it can get established.
Oh, and one more plus… the plant is an important nectar source for many insects and a larval food plant for many butterflies and moths. The flowers are visited by many species of native and non-native bees.
