Controlling Common Chickweed in Strawberries

IDENTIFICATION:

Common chickweed is low growing, usually 4″ to 8″ tall. Leaves are a bright pale green, tear-shaped, and attached to the stem on opposite sides by a slender stalk. Stems are lighter in color and very easily broken. Where stems touch the ground, new roots are formed. This gives the common chickweed a spreading growth habit.

Common chickweed flowers are small and white. Flowers have five petals, with each petal so deeply divided that it appears to be split in two. This gives the flower a ‘starlike’ appearance leading to the plant’s scientific name, Stellaria.

A similar-appearing weed, mouse-ear chickweed, is found in strawberry fields. Flowers of the two plants are similar, but leaves of mouse-ear chickweed are dark green and hairy.

CHARACTERISTICS:

Common chickweed is a winter annual. Winter annuals germinate in the late summer or fall, overwinter as small plants, then put on growth during the cool months of the spring. Most winter annuals cannot withstand hot weather, and will set seed and die in June or July. Common chickweed generally follows this pattern, but will sometimes also be seen to germinate through the spring and early summer, and plants can occasionally survive the summer in shaded areas.

Winter annuals are a particular problem for strawberry growers. In other crops, spring and/or fall tillage would disrupt the life cycle of this weed. In strawberries, the lack of tillage at these times and winter protection with mulch allows these weeds to survive and thrive. Renovation does not affect these weeds, as they have generally produced seeds by July.

Both common and mouse-ear chickweed are in the Caryophyllaceae, or ‘pink’ family. Well-known plants in this family include garden flowers such as carnations, Dianthus and Maltese cross. Other weeds in this family include mouse-ear chickweed, white cockle, and knawel.

Common chickweed is edible, and leaves can be added to salads.

IMPORTANCE:

Because common chickweed is low growing and shallow rooted, its ability to compete with strawberries is limited. It can, however, make harvest difficult and pick-your-own operations unattractive. If chickweed is left uncontrolled for many years, populations can build up to the point where yields are impacted. When common chickweed is present in great numbers, lower leaves of strawberry plants can be shaded. In addition, heavy infestations of this weed could block airflow around strawberry plants, increasing the likelihood of fungal disease problems.

MANAGEMENT:

CHEMICAL: 2,4-D materials are not effective on this weed. Labeled rates of Sinbar applied at mulching over emerged chickweed are generally ineffective. Effective control can be achieved with an application of Devrinol in late August. Since Devrinol does not control emerged weeds, it is important to make the application before emergence. While Dacthal can also control this weed from seed, residual control is too short to make this application cost effective.

NONCHEMICAL: Cultivation between rows and a thorough hoeing in the late fall can be used to destroy overwintering seedlings. Control by hand is possible in the spring. This should be done as early in the season as possible, before plants begin to spread. Plants are not killed unless roots are destroyed, so a weeding tool which scrapes just below the surface of the soil would be most effective. Crop rotation may be one of the most effective ways of preventing the buildup of common chickweed. The conditions so favorable to common chickweed in strawberries are not present in most other crops. Rotating out of strawberries every few years for several years at a time may be useful in keeping common chickweed and other strawberry weeds in check.

INTEGRATING CHEMICAL AND NONCHEMICAL CONTROL: Because 100% control with herbicides may be difficult to achieve, growers may wish to integrate nonchemical and chemical measures to boost control. Crop rotation can be used to reduce seed populations in the soil. In addition, growers can use cultivation, hand weeding, and hoeing to eliminate plants that have escaped control with herbicides. To prevent seed production, all plants, should be eliminated by early to mid-May.

Prepared by: M.J. Else and A.R. Bonanno, University of Massachusetts Extension, Adapted from Strawberry Weed Fact Sheet SF96-W1.

Reviewed by: Mary Concklin, UConn IPM. 2012

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