By the HMNDP Editorial Team, independent reporting on lawn care, landscaping, and the green-industry business.
Last reviewed: June 2026
Florida weeds, identified and controlled in one place
Florida weeds fall into three categories you can tell apart by sight: broadleaf weeds (wide leaves, often with flowers), grassy weeds (blade-like, look like grass), and sedges (triangular stems, glossy V-shaped leaves). Identify the category first, then match the species, then pick a control method. Florida’s subtropical climate lets most weeds grow year-round, so timing matters more here than up north.
This guide is organized by what you can observe in your yard, not by names you may not know yet. Start with leaf shape and where the weed is growing, then confirm the species and its specific control method. Identification details draw on the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) and the Florida Department of Agriculture and Consumer Services (FDACS) noxious weed lists.
The three weed categories: broadleaf vs. grassy vs. sedge
Sorting a Florida weed into one of three categories is the single most useful ID step because it determines which herbicide will work. Broadleaf weeds have wide leaves and net-like veins. Grassy weeds have narrow blades and parallel veins. Sedges have solid triangular stems (“sedges have edges”) and grow faster than turf in summer. The wrong category means the wrong product.
| Category | How to recognize | Florida examples | Herbicide that targets it |
|---|---|---|---|
| Broadleaf | Wide leaves, net veins, often flowers | Dollarweed, betony, Florida pusley | Selective broadleaf (2,4-D, dicamba blends) |
| Grassy | Narrow blades, parallel veins, looks like grass | Crabgrass, goosegrass, cogongrass | Pre-emergent, or grass-selective post-emergent |
| Sedge | Triangular stem, glossy V-shaped leaf, fast-growing | Yellow and purple nutsedge, kyllinga | Sedge-specific (sulfentrazone, halosulfuron) |
Roll the stem between your fingers. If it feels three-sided, you have a sedge, and most broadleaf or crabgrass products will not touch it. This single test saves homeowners from buying the wrong bottle.
Identify the weed by what you see
To identify a Florida weed, work from three observations: leaf shape, flower color, and growth location. A wide round leaf in a wet spot points to dollarweed. A grass-like clump that outgrows your lawn points to nutsedge or crabgrass. A purple or pink flower narrows the field fast. Use the table below as a quick diagnostic before reading the species detail.
| What you observe | Likely weed | Category |
|---|---|---|
| Round, coin-shaped leaf, stem in the center, damp area | Dollarweed (pennywort) | Broadleaf |
| Glossy blade taller than your turf, triangular stem | Nutsedge | Sedge |
| Low, spreading grass with finger-like seed heads | Crabgrass | Grassy |
| Tall whitish plumes, leaf with off-center white midrib, rough edges | Cogongrass (noxious) | Grassy |
| Small purple or pink tubular flowers, square stem | Florida betony or henbit | Broadleaf |
| Star-shaped white flower, low mat in lawn | Florida pusley | Broadleaf |
Dollarweed (pennywort)
Dollarweed, also called pennywort (Hydrocotyle species), is a broadleaf weed with a round, bright-green leaf that looks like a tiny lily pad, with the stem attached at the center of the leaf. It thrives in overwatered lawns and wet, poorly drained spots. Seeing dollarweed usually means you are watering too much. Fix the moisture and you remove its advantage.
Nutsedge (sedge)
Nutsedge, also called nutgrass, is a sedge with glossy, stiff, V-shaped leaves and a triangular stem that grows noticeably faster than surrounding turf, especially in July and August. Yellow nutsedge has light-green leaves and tan seed heads. Purple nutsedge has darker leaves and reddish heads. Both spread by underground tubers (“nutlets”), which is why pulling rarely works.
Crabgrass (grassy)
Crabgrass (Digitaria species) is a low, spreading summer grassy weed that roots at the nodes and produces finger-like seed heads. It loves thin lawns, sidewalk edges, and sunny compacted soil. A single plant can produce thousands of seeds, so the practical control is a pre-emergent applied before the seeds sprout rather than fighting mature plants.
Cogongrass (noxious, do not ignore)
Cogongrass (Imperata cylindrica) is a state and federally listed noxious grassy weed in Florida and one of the most aggressive invasive plants in the Southeast. Look for dense circular patches, leaves with an off-center whitish midrib and finely serrated razor-like edges, and fluffy silvery-white seed plumes in spring. It displaces native plants and burns extremely hot in wildfires.
Common Florida lawn weeds vs. invasive and noxious weeds
Common lawn weeds (crabgrass, dollarweed, nutsedge, pusley) are nuisances you control at the yard level. Invasive and noxious weeds are a legal and ecological category: Florida’s FDACS maintains a Noxious Weed List, and species like cogongrass and tropical soda apple carry movement and disposal rules. The distinction matters because noxious species often require reporting and careful disposal, not just spraying.
| Type | Examples | Where they appear | Your obligation |
|---|---|---|---|
| Common lawn weed | Crabgrass, dollarweed, nutsedge, Florida pusley | Lawns, garden beds, sidewalk cracks | Control at your discretion |
| Invasive / noxious | Cogongrass, tropical soda apple, air potato | Natural areas, pastures, lawn edges, fence lines | Often regulated; check FDACS guidance before moving or composting |
Where a weed grows is a clue in itself. Lawn weeds cluster in turf and beds. Many invasives push in from natural areas, ditches, and fence lines, which is why new Florida residents often first spot cogongrass at the back edge of a property. For a broader homeowner reference, see our overview of common lawn weeds.
Florida weeds with purple flowers
Florida weeds with purple or pink flowers most often turn out to be Florida betony, henbit, lawn burweed relatives, or wild violet. Florida betony has square stems, tubular pinkish-purple flowers, and a distinctive white segmented “rattlesnake” tuber underground. Henbit shows up in cool months with purple flowers above scalloped leaves. Color alone is not enough, so confirm leaf and stem shape.
If a purple-flowered weed has a square stem, it is likely in the mint family (betony or henbit) and responds to selective broadleaf herbicides. We cover this visual ID question in more depth in our guide to the weed with purple flowers.
How to kill Florida weeds without killing your grass
To kill Florida weeds without harming your lawn, match the herbicide to the weed category and to your turf type. Selective broadleaf products target dollarweed and betony while sparing grass. Sedge-specific products handle nutsedge. Pre-emergents stop crabgrass before it sprouts. Always confirm the label lists your grass (St. Augustine, Bahia, Bermuda, Zoysia, centipede), because St. Augustine is sensitive to several common actives.
| Weed | Selective chemical control | Organic / non-chemical option | Best timing in Florida |
|---|---|---|---|
| Crabgrass | Pre-emergent (prodiamine, dithiopyr) before sprouting | Thicken turf, hand-pull seedlings, mow tall | Pre-emergent late Jan to mid Feb (soil ~65°F) |
| Dollarweed | Broadleaf blend (2,4-D plus dicamba where labeled) | Reduce irrigation, fix drainage, spot-pull | Active growth, spring through fall |
| Nutsedge | Sulfentrazone or halosulfuron (sedge-specific) | Improve drainage, repeated removal of tubers | Early summer when actively growing |
| Florida betony | Selective broadleaf herbicide | Dig tubers, smother with mulch in beds | Fall and spring growth flushes |
| Cogongrass | Glyphosate (non-selective) plus follow-up; consult Extension | Repeated mowing weakens but rarely eradicates | Late summer to fall for translocation |
For broadleaf weeds, spot-spray on a calm day above 60°F and avoid spraying stressed or dormant turf. For a fuller method walkthrough including spreader and sprayer setup, see how to get rid of weeds.
- Identify the category (broadleaf, grassy, sedge) using the stem and leaf test.
- Confirm your turf type and read whether the herbicide label lists it as safe.
- Choose pre-emergent (not yet sprouted) or post-emergent (already visible).
- Treat when the weed is actively growing, not in drought stress or dormancy.
- Re-treat sedges and tuber weeds on the label interval, since one pass rarely finishes them.
When to apply weed killer and pre-emergent in Florida
Timing in Florida differs from the rest of the country because weeds grow nearly year-round. The key pre-emergent window for summer weeds like crabgrass is roughly late January through mid-February in much of the state, when soil temperatures approach 65°F. A second pre-emergent for cool-season weeds goes down in early fall, around October. Post-emergent sprays work best on actively growing weeds.
Southern Florida runs earlier than the Panhandle, so adjust by your local soil temperature rather than a fixed calendar date. UF/IFAS county Extension offices publish region-specific timing if you want to confirm for your county.
Are common Florida weeds toxic to pets or children?
Some common Florida weeds and the products used on them can pose risks to pets and children, though most lawn weeds are low-toxicity. The bigger hazards are usually the herbicides during application and certain invasive plants. Keep pets and kids off treated areas until sprays dry, and identify any berry- or sap-producing weed before letting children near it.
| Plant / product | Concern level | Note |
|---|---|---|
| Dollarweed, crabgrass, pusley | Low | Generally not toxic; nuisance only |
| Nutsedge | Low | Not considered toxic to pets |
| Tropical soda apple (invasive) | Moderate to high | Spiny; fruit can sicken livestock and is not for children |
| Herbicide sprays (any) | Variable | Follow label re-entry time; keep off until dry |
When in doubt, photograph the plant and confirm the species before assuming it is harmless. For more identification and care references, browse the HMNDP learn hub.
Frequently Asked Questions
What are the most common weeds in Florida lawns?
The most common Florida lawn weeds are crabgrass (grassy), dollarweed or pennywort (broadleaf), nutsedge (sedge), Florida pusley, and Florida betony. Crabgrass invades thin sunny turf, dollarweed signals overwatering, and nutsedge outgrows the lawn in summer heat. Identifying which category each belongs to (broadleaf, grassy, or sedge) determines which herbicide will actually control it.
How do I identify a weed in my Florida yard?
Start with three observations: leaf shape, flower color, and where it grows. Roll the stem to test for a triangular shape (a sedge) versus round (grass) or square (often a mint-family broadleaf). Wide net-veined leaves mean broadleaf; narrow parallel-veined blades mean grassy. Match those traits to a species, then confirm against UF/IFAS photos before choosing a control product.
Which Florida weeds have purple flowers?
Florida weeds with purple or pink flowers are most often Florida betony, henbit, and wild violet. Florida betony has square stems and a white segmented underground tuber. Henbit appears in cooler months with scalloped leaves. Flower color alone is not enough to identify a weed, so confirm stem shape and leaf pattern, since several unrelated species share purple blooms.
How do I kill weeds in my Florida lawn without killing the grass?
Match a selective herbicide to both the weed category and your turf type. Broadleaf blends control dollarweed and betony, sedge-specific products handle nutsedge, and pre-emergents stop crabgrass before it sprouts. Confirm the label lists your grass, because St. Augustine is sensitive to several common actives. Spray only actively growing weeds on a calm day above 60°F.
What is the most invasive or noxious weed in Florida?
Cogongrass (Imperata cylindrica) is among the most aggressive noxious weeds in Florida and is listed by both state and federal authorities. It forms dense circular patches, has leaves with an off-center white midrib and razor-like edges, and produces silvery seed plumes in spring. It displaces native plants and burns intensely in fire, so the FDACS treats it as a regulated species.
What is the difference between dollarweed and nutsedge?
Dollarweed is a broadleaf weed with round, coin-shaped leaves and a stem attached at the leaf center, thriving in wet soil. Nutsedge is a sedge with stiff, glossy, V-shaped grass-like leaves and a triangular stem that outgrows turf in summer. They need different herbicides: a broadleaf product for dollarweed and a sedge-specific product for nutsedge.
When is the best time to apply weed killer or pre-emergent in Florida?
Apply pre-emergent for summer weeds like crabgrass when soil approaches 65°F, roughly late January to mid-February in much of Florida, with a second application around October for cool-season weeds. Post-emergent sprays work best on actively growing weeds, not dormant or drought-stressed plants. South Florida runs earlier than the Panhandle, so track local soil temperature rather than a fixed date.
Are any common Florida weeds toxic to pets or children?
Most common Florida lawn weeds (dollarweed, crabgrass, nutsedge, pusley) are low-toxicity nuisances. The larger risks are usually herbicide sprays during application and certain invasives like tropical soda apple, which is spiny and bears fruit that can sicken livestock. Keep pets and children off treated lawns until sprays dry, and identify any berry- or sap-producing plant before allowing contact.