How do we control Florida Lawn Weeds? We begin by identifying the weeds into three groups: Broadleaf Weeds, Grass Weeds and Sedge Weeds. To control common Florida lawn weeds, use a combination of proper lawn care practices, targeted chemical herbicides, and manual removal.

Broadleaves (Dollar Weed, Florida Pusley, Spanish Needles)

Broadleaf weeds have wide leaves with net-like veins that grow from a stem. They are generally the easiest to target without harming your turfgrass.

• Cultural Control: Reduce watering frequency. Dollarweed thrives in overwatered, saturated soil.
• Chemical Control: Apply a selective post-emergent broadleaf herbicide containing Atrazine (for St. Augustine and Centipede lawns) or 2,4-D (for Zoysia and Bermuda lawns).
• Prevention: Spread a pre-emergent herbicide in early spring (February) and fall (October).

Dollar Weed ~ Torpedo Grass ~ Purple Sedge (images UF/IFAS)

Grasses (Crabgrass, Torpedo Grass, Southern Sandbur)

Grassy weeds have long, thin leaf blades that grow from a round stem, often jointed.

• Cultural Control: Mow at the highest recommended height for your grass type to shade out weed seeds.
• Chemical Control: Use a selective post-emergent like Quinclorac for crabgrass in Zoysia or Bermuda. For St. Augustine lawns, post-emergent options are highly limited, and spot-treating with a non-selective herbicide like Glyphosate may be necessary.
• Prevention: Pre-emergent herbicides are critical. Apply Dithiopyr or Prodiamine in late winter before soil temperatures reach 55°F.

Sedges (Purple and Yellow Nutsedge)

Sedges are not true grasses and have long, thin leaves that grow from a triangular stem, not jointed. Regular grass killers will not affect them.

• Cultural Control: Improve soil drainage and repair leaking irrigation heads, as sedges love wet areas. Be careful when hand-pulling mature nutsedges, as this triggers underground “nutlets” to sprout rapidly.
• Chemical Control: Apply a specialized sedge killer containing Halosulfuron-methyl or Sulfentrazone. These travel down to kill the underground tuber systems.

Remember, Weed identification is the first step in Lawn Weed Control. Please consult the University of Florida publications for specific recommendations:

1. ENH884 – Weed Management Guide for Florida Lawns
2. ENH1311 – Florida Homeowner Herbicide Guide: Considerations, Applications, and Selection

Visit the UF/IFAS Lake County Extension Plant Clinic for assistance in weed identification. Speak to Master Gardener Volunteers from Monday-Friday, 10 am to 2 pm. We are at 1951 Woodlea Road, Tavares, FL 32778, t: 352-343-4101.

This post was written with the help of MGV Clayton Yuen, Lake County Master Gardener Volunteer. Thank you!

3