A mild winter during 1999–2000 and springlike conditions in February and March have probably led to the great abundance of common chickweed (Stellaria media) now being seen. Common chickweed is a cool-season annual (also known as a winter annual) member of the Pink family (Caryophyllaceae) that reproduces by seeds and creeping stems. Normally, cool-season annuals germinate in the autumn, flower the following spring, and die soon after summer temperatures rise; common chickweed, however, may occasionally persist through summer in sites protected from heat and drought. Common chickweed occurs in cool, moist, shady, often compacted, fertile sites in spring and autumn.
Common chickweed often forms large, dense patches in mowed areas but grows more upright in unmowed settings. The hairy, creeping stems root at nodes and produce shallow, fibrous roots. Leaves are bright green, opposite, simple, broadly oval, and usually less than 1 inch long. Its small, spring-borne white flowers are approximately 1/2 inch in diameter, have five petals, and are star shaped.
To control common chickweed without chemicals, maintain turf density and health by employing proper turf culture and mechanically remove the weed from the site. For chemical control, apply postemergence herbicides (for example, products containing 2,4-D; MCPP; dicamba, clopyralid, or triclopyr) in midspring or mid- to late autumn during active growth; apply preemergence herbicides (for example, products containing benefin + trifluralin, dithiopyr, pendimethalin, or prodiamine) before germination in late summer or early autumn. Because most common chickweed plants are currently senescing and will soon die, application of chemical weed controls is not recommended any longer this spring.