Almost every wasted weed control dollar around here comes from the same error: buying a product for the wrong category of weed. Sedges are not grasses. Grasses are not broadleaves. A product that handles one may do absolutely nothing to another, and on centipede, using the wrong thing can damage the lawn worse than the weed was.
The three categories
Grassy weeds have long narrow blades with parallel veins, growing in a two-ranked pattern, alternating sides of the stem. Crabgrass, goosegrass, bahiagrass and annual bluegrass fall here. These are the hardest to control selectively, because chemically they are close relatives of your lawn.
Broadleaf weeds have wider leaves with branching veins and usually obvious flowers. Dollarweed, Virginia buttonweed, clover, chickweed and spurge live here. These are the most straightforward to control selectively, though centipede sensitivity still limits your options.
Sedges look like grasses and are not. The identifying feature is simple and reliable: roll the stem between your fingers. Sedge stems are triangular. Grass stems are round or flattened. Nutsedge is the common one, and it needs sedge-specific products, since ordinary broadleaf herbicides will not touch it.
That triangular stem test takes two seconds and saves people a lot of money.
Annual or perennial matters too
Annuals complete their life in a season and come back from seed. That means pre-emergent control, applied before germination, is the effective tool. Crabgrass and annual bluegrass are the classic examples.
Perennials come back from roots, tubers or rhizomes year after year. Pre-emergent does nothing to an established perennial. Nutsedge regrows from tubers, and torpedograss and bermuda spread by rhizome, which is why they are so persistent.
What we see most in Jefferson County lawns
Crabgrass: summer annual, spreads outward from a center in a star pattern, coarse light-green blades. Pre-emergent in late winter is the control point.
Annual bluegrass: cool-season annual, comes up in fall and winter, lighter green than the lawn, produces obvious seedheads even when mowed short. Fall pre-emergent timing.
Dollarweed: bright green round leaves with the stem attached at the center like a tiny umbrella. Almost always signals too much water, whether from irrigation or drainage.
Nutsedge: lighter yellow-green, grows faster than the lawn so it sticks up between mowings, triangular stem, reproduces from tubers.
Virginia buttonweed: low sprawling perennial with paired leaves and small white flowers, roots at the nodes, thrives in wet ground.
Doveweed: thick fleshy stems, narrow shiny leaves, germinates later in the season than most, loves wet spots.
Bahiagrass: coarse, tough, with a distinctive Y-shaped seedhead, common as a pasture escape on properties out toward Lamont and Capps.
Spurge: low flat mat, small paired leaves, stems exude milky sap when broken. A hot-weather colonizer of thin, bare or compacted areas.
Weeds are a symptom before they are a problem
This is the part worth internalizing. Weeds establish where turf is not thick enough to exclude them, and the pattern of which weeds you have tells you what is wrong.
- Dollarweed, doveweed and buttonweed clustered in one area means that area stays too wet
- Spurge and knotweed usually mean compaction and thin turf
- Broad weed pressure across an entire lawn often means the grass is being mowed too short
- Weeds concentrated in shade means the grass there is not getting enough light to compete
Kill the weed without changing the condition and you get bare ground in the same spot, which fills with something else.
Before you spray anything
Confirm what the weed is. Confirm your grass species is named on the product label as tolerant, which matters most on centipede. Use the rate listed for your grass, which is often lower for centipede. Respect the label temperature limits, since summer heat here regularly exceeds them. Spot treat rather than blanket spraying. And do not apply to stressed or dormant turf.
If you are not sure what you are looking at, your county extension office can identify it. UF/IFAS Extension does this routinely and a correct identification is worth more than a guessed product.
The control that costs nothing
A dense lawn is the best weed control available. Correct mowing height for the species, restrained fertility, deep infrequent watering, and relieved compaction produce a canopy that most weed seed cannot establish in. We have watched weed problems resolve simply because a mowing height went up an inch and stayed there.
Bring us a photo or point at it while we are on site and we will tell you what it is. Get in touch anytime.