Lesser Trefoil – Yellow Suckling Clover [Trifolium dubium]

Description: Lesser Trefoil, popularly known as Yellow Suckling Clover, is a widespread annual weed predominantly found in UK lawns. The weed’s low-growing mat formation allows it to thrive even in environments with frequent and close mowing, making it a recurring challenge for many gardeners.

While it’s easy to mistake Lesser Trefoil for Black Medic due to their striking resemblance, the former can be distinguished by its slender stems that don’t root periodically. The trifoliate leaves, each bearing three leaflets on a short stalk, are reminiscent of clover leaves but are marginally smaller. Initially yellow, its flowers transition to a brown hue as they mature, blooming from May through October. The weed has a preference for dry, alkaline soils that are deficient in nitrogen.


  1. Cultural Control:
    • Hand Weeding: A viable solution for gardens with a limited infestation, hand weeding can effectively reduce the presence of Lesser Trefoil. For enhanced effectiveness, rake the weed into an upright position before mowing to weaken its structure and prevent further growth.
  2. Chemical Control:
    • Selective Herbicides: If you’re considering chemical interventions, opt for a selective weed killer proven effective against Lesser Trefoil. Products containing mecoprop-p are particularly potent in combating this weed. If the initial application doesn’t eradicate the weed entirely, a subsequent treatment after six weeks may be required. Always ensure you’re equipped with the recommended protective gear when handling chemicals and strictly adhere to the manufacturer’s guidelines for safety and efficacy. For a comprehensive guide on applying selective herbicides, refer to our Lawn Weeds page.
  3. Lawn Repair:
    • Soil and Grass Seed Mixture: Once Lesser Trefoil has been successfully removed or suppressed, there might be visible patches or barren spots left behind on the lawn. These areas can be rejuvenated by filling them with a blend of appropriate soil and grass seed. This not only aids in lawn recovery but also prevents the weed from making a comeback.

In conclusion, while Lesser Trefoil can be a persistent nuisance for lawn enthusiasts, a combination of cultural, chemical, and repair strategies can ensure a lush, weed-free garden. As always, when employing chemical solutions, prioritizing safety is paramount.

John Storm

Oliver Thompson
Lawn Care Expert

About Oliver: Oliver Thompson, a seasoned lawn care expert from the Cotswolds with over two decades of experience, invites all enthusiasts to join him in exploring the world of lawns, sharing knowledge, and fostering a vibrant community of lawn enthusiasts. More info

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