· Michael Blair
Weed control products are selective, so identifying what you have decides whether an application does anything at all. Three categories cover almost everything in a Nashville lawn.
Broadleaf weeds
Dandelion, clover, plantain, chickweed, henbit and wild violet. Wide leaves, obviously different from grass, and controlled by standard broadleaf herbicides.
Wild violet is the stubborn one here and usually needs repeat applications and the right timing in autumn.
Grassy weeds
Crabgrass, goosegrass and dallisgrass. They look like grass, which is what makes them difficult — a broadleaf product does nothing and a non-selective one kills the lawn.
Prevention with pre-emergent is far more effective than post-emergent control, which is limited and timing-sensitive.
- Broadleaf: wide leaves, standard herbicide works
- Grassy: looks like grass, prevention beats cure
- Sedge: triangular stem, needs a sedge-specific product
- Roll a stem between your fingers to identify sedge
- Nutsedge indicates a wet area worth investigating
Sedges
Nutsedge is the common one and it is neither a broadleaf nor a true grass. Roll the stem between your fingers — sedge stems are triangular, grass stems are round.
It needs a sedge-specific herbicide, and broadleaf products have no effect at all on it.
Weeds tell you something
Nutsedge indicates persistently wet soil. Clover often indicates low nitrogen. Prostrate knotweed indicates compaction. Moss indicates shade, damp and low pH together.
Treating the weed without the condition means treating it again next year.