Trifolium pratense L.
This species is often confused with white clover, a closely related species; however, leaves of red clover are larger than white clover and flowers are red or pink. Cultivated as a forage crop and for medical purposes, red clover seed occasionally escapes and is transported to lawns.
Red clover belongs to the legume family (Fabaceae) and is classified as a short-lived perennial. Plants have spreading or erect stems and form clumps and small patches. Foliage typically dies back in winter and new leaves are produced from crown tissue in spring. Foliage may persist and remain visible during mild winters. Red clover produces flowers from late spring to early summer, and occasionally in late summer and fall. Individual flowers are replaced by small seedpods containing 1 or 2 kidney-shaped seeds. Seed germination occurs during cool, moist periods in spring and fall. Like other legumes, red clover exists symbiotically with nitrogen-fixing Rhizobia bacteria which produce nodules on roots and convert atmospheric nitrogen into a plant-available form.
Red clover stems are somewhat hairy, spreading, or erect. Leaves are made up of three oval or oblong leaflets (trifoliate arrangement) up to 2 inches in length and ¾ inch in diameter and arise alternately on stems. Margins of leaflets are smooth, with tiny hairs projecting outward. A white or light green inverted V-shaped pattern often referred to as a watermark or chevron, is usually visible in the middle of each leaflet. Leaflets lack petioles and two stipules are located at the base of the leaf. Mature inflorescences are spherical or globe-shaped, approximately ¾ to 1 inch in diameter, and contain numerous small pink or purplish-pink flowers. Red clover has a deep taproot that allows survival under drought stress conditions.
Red clover is more likely to form clumps and patches in new lawns that are not adequately fertilized with nitrogen. Infestations of red clover can be reduced by improving turf density through good establishment procedures and the use of turfgrasses well-adapted to site conditions. This weed is best controlled by herbicides containing dicamba, clopyralid, fluroxypyr, and quinclorac. Regrowth of foliage sometimes occurs following spring herbicide applications. Fall applications of herbicides are often the most effective means of controlling red clover.es.