University of Maryland Extension

Black Medic

(More Lawn Weeds)

Black Medic
Medicago lupulina

flowering black medic
Photo: Black Medic, Medicago lupulina

General description

Black Medic is usually first noticed when it produces numerous round yellow flowers in clover like clusters. Flowers eventually form black seedpods that persist on dark brown to black prostrate stems. A legume that is a summer annual with alternate compound leaves with 3 leaflets that closely resembles clover. Toothed stipules are present at the petiole bases. Forms a shallow taproot with small nodules. Often mistaken for wood sorrel (Oxalis).

close up of black medic
Closeup of black medic

Management In Lawns

  • Cultural practices
    Maintain healthy, dense turf that can compete and prevent weed establishment.

  • Mechanical Management
    Hand pulling or using an appropriate weeding tool are the primary means of mechanical weed control in lawns. This is a viable option at the beginning of an infestation and on young weeds. Hand pulling when the soil is moist makes the task easier. Weeds with tap roots like dandelions or have a basal rosette (leaves clustered close to the ground) like plantain are easier to pull than weeds such as Bermudagrass (wiregrass) or creeping Charlie (ground ivy) that spread with stolons or creeping stems that root along the ground.

  • Chemical Treatment in Lawns 
    Herbicides should be used as a last resort because of the potential risks to people, animals, and the environment. Be aware of these precautions first. 
    If you chose this option, spot treat weeds with a liquid, selective, postemergent, broadleaf weed killer applied when weeds are actively growing. Look for a product with one or more of the following active ingredients: 
    2, 4-D, MCPP (mecoprop), Dicamba* or Triclopyr.

    *Do not spray herbicides containing dicamba over the root zone of trees and shrubs. Roots can absorb the product possibly causing plant damage. Refer to the product label for precautions. 

  • Organic Lawn Herbicides

 

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