White clover and birds-foot trefoil have been prominent plants in some Iowa lawns this spring and summer. Both are valuable agricultural crops. They have become common in many lawns because they are prolific seed producers and adapt well to mowing and other lawn care practices.
White clover (Trifolium repens) is a creeping perennial. The stems root at the nodes where they touch the soil. The leaves are composed of 3 leaflets. Plants bloom profusely in early summer. Flower heads consist of 20 to 40 individual white to pinkish-white, fragrant flowers.
White clover has been a common plant in many Iowa lawns this year. The weather from mid spring to early summer was dry and relatively cool. Many lawns went dormant because of the dry conditions. White clover, however, is more drought tolerant. The white clover prospered and bloomed profusely in early summer.
White clover is native to Europe and Asia, but has become naturalized in much of the United States. White clover is grown for livestock grazing, soil improvement, and erosion control. In years past, it was often used in lawn seed mixtures.
Birds-foot trefoil (Lotus corniculatus) is a warm-season perennial. The plant has an upright spreading habit and grows about 2 feet tall. The dark green leaves appear to be composed of 5 leaflets. The compound leaves actually consist of 3 leaflets and 2 broad leaf-like stipules at the base of the leaf stalk. Plants produce small, pea-like flowers. Flowers are bright yellow to deep orange and are sometimes tinged with red. Flowers are borne in a cluster of 4 to 8 at the ends of stems. The one inch long fruits (seed pods) somewhat resemble toes on a bird's foot, hence the common name of birds-foot trefoil. At maturity, the pods split and the halves twist, scattering the seeds. In lawns, mowers also help to scatter the seeds.
Birds-foot trefoil is native to Europe and Asia, but has become naturalized in much of the United States. It tolerates compacted, infertile, and poorly-drained soils. Birds-foot trefoil is also drought and salt tolerant. Birds-foot trefoil is grown as a forage crop and also as a groundcover.
Gardeners who would like to control birds-foot trefoil and/or white clover in their lawns can use a postemergence broadleaf herbicide product in the fall. Combination products that contain 2 or more of the following herbicides: 2,4-D, MCPP, dicamba, and triclopyr are most effective. One application this fall should be sufficient to kill existing plants. Since both plant species can produce large quantities of seeds, additional control measures may be necessary next year.
This article originally appeared in the July 22, 1992 issue, pp. 1992 issue, pp. 129-130.