Saturday, May 3, 2008

Turf - Black Medic

Black medic is now flowering in turf areas. The following is information on this weed.

Black Medic (Medicago lupulina) is a yellowed flowered leguminous weed of turf and minimally maintained areas. It is related to alfalfa and has compound leaves that are arranged alternately with three, wedge to oval shaped leaflets. The center leaflet is stalked and the side leaflets occur close to the stem. The yellow flower is ball shaped but is smaller than white clover. Black Medic commonly occurs as a summer annual but can survive the winter as a tender perennial. It is common in compacted soils such as high traffic areas near sidewalks and is more prevalent in sites that receive limited nitrogen fertilization.

Many broadleaf post emergence herbicides have activity against Black Medic in turf; however 2,4-D will not provide control. Use of a product with triclopyr, dicamba, fluroxypyr, or clopyralid as an active ingredient is recommended. Drive (quinclorac), is effective against Black Medic and is also a good crabgrass herbicide. Spring applications made before the end of May are most effective. Black medic can be difficult to kill when under water stress and multiple applications may be needed in summer.

Gordon Johnson, Extension Horticulture Agent, UD, Kent County

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