Weed identification - Ask Extension
Good morning…reviewed your web site for weed identification but I do not see this one. It might be smartweed? Seems to grow mostly in the drainage...
Knowledgebase
Weed identification #800324
Asked July 10, 2022, 11:22 AM EDT
Good morning…reviewed your web site for weed identification but I do not see this one. It might be smartweed? Seems to grow mostly in the drainage area of yards in my neighborhood. It is also green and turns yellow over time.
Charles County Maryland
Expert Response
This looks like Virginia Buttonweed (Diodia virginiana), a difficult-to-control native perennial weed. If left unmanaged, this can grow into dense mats. Do not mow too low as this will increase fragmentation of the leaves and spreading. Lawn clipping collection is useful to prevent returning leaf fragments to the site.
As you noticed, this weed favors moist areas, so if you can reduce irrigation (if applicable) to prevent excess moisture, that will help to some extent. Herbicide applications may be required to manage this species. Look for a post-emergent weed control product with a combination of the active ingredients 2,4-D, dicamba, and MCPP (also called mecoprop). Repeated applications may be necessary for this tough weed. Alternatively, glyphosate can be used on patches of the weed if turf is already thin, and then reseed or sod after an appropriate wait period (ideally late August - September). Read and follow product label instructions for any herbicide you decide to use. 2,4-D and dicamba can drift and volatilize (evaporate and expose other plants) in hot temperatures and damage other desirable plants, so be sure to read the label instructions about application restrictions regarding weather conditions.
If the weed is a recurring problem, care of the turfgrass might need examining for conditions that suit the weed's survival. This can include soil testing to determine if the soil pH needs adjusting, or to see if changes in fertilization would improve the vigor of the grass so it can more easily out-compete weeds. Improving the drainage of wet areas or reducing wetness, such as by redirecting any runoff (like from a nearby roof downspout outlet) will help discourage wet-loving weeds like Buttonweed from recolonizing the site while improving turf growth.
Miri
As you noticed, this weed favors moist areas, so if you can reduce irrigation (if applicable) to prevent excess moisture, that will help to some extent. Herbicide applications may be required to manage this species. Look for a post-emergent weed control product with a combination of the active ingredients 2,4-D, dicamba, and MCPP (also called mecoprop). Repeated applications may be necessary for this tough weed. Alternatively, glyphosate can be used on patches of the weed if turf is already thin, and then reseed or sod after an appropriate wait period (ideally late August - September). Read and follow product label instructions for any herbicide you decide to use. 2,4-D and dicamba can drift and volatilize (evaporate and expose other plants) in hot temperatures and damage other desirable plants, so be sure to read the label instructions about application restrictions regarding weather conditions.
If the weed is a recurring problem, care of the turfgrass might need examining for conditions that suit the weed's survival. This can include soil testing to determine if the soil pH needs adjusting, or to see if changes in fertilization would improve the vigor of the grass so it can more easily out-compete weeds. Improving the drainage of wet areas or reducing wetness, such as by redirecting any runoff (like from a nearby roof downspout outlet) will help discourage wet-loving weeds like Buttonweed from recolonizing the site while improving turf growth.
Miri
