Getting Ahead of Weeds Before Season: Fall Weed Control for Palm Beach Lawns

Getting Ahead of Weeds Before Season: Fall Weed Control for Palm Beach Lawns

Lawn Squad of The Palm Beaches • November 2026 • The Palm Beaches, FL

If you are reading this, your lawn may have come out of the summer rainy season with more than grass growing in it. Patches of shiny sedge along the driveway, round dollarweed leaves spreading through the backyard, and low mats of spurge in the thin spots near the walkway are common sights across the Palm Beaches by October.

With season approaching and the dry months ahead, fall is a great time to clean things up. Here is how weed control works in Palm Beach lawns this time of year.

Why Fall Is a Good Window

Summer heat limits what can safely be used on St. Augustine. Many herbicides labeled for St. Augustine and zoysia have temperature restrictions, and some can injure the grass when applied in hot weather. As temperatures ease in November, more options become safer, and the grass is under less heat stress.

At the same time, many weeds that grew through the summer are still present and actively growing, which makes them good targets. Treating them now gives the lawn several months to fill in before spring.

Sedges

Sedges, including nutsedge and kyllinga, are among the most common weeds in Palm Beach lawns. They look like grass but are shinier, often lighter green, and grow faster than the turf. Many have triangular stems. Sedges thrive in wet soil, which makes them common after the rainy season and in overwatered lawns.

Sedges require products specifically labeled for sedge control. General broadleaf herbicides do not control them.

Dollarweed

Dollarweed, or pennywort, has round, shiny, coin-sized leaves and spreads by runners. It is almost always a sign of too much water. Cutting back irrigation is the single most effective step against dollarweed, and post-emergent products labeled for it can help.

Spurge, Doveweed, and Other Broadleaf Weeds

Spurge forms low, spreading mats, often in thin or stressed areas. Doveweed has shiny, grass-like leaves and thrives in moist conditions during the warm season. Florida pusley, chamberbitter, and other broadleaf weeds show up in many lawns too. Most are easier to control while they are young and actively growing.

Irrigation Is the First Weed Control Step

Many of the Palm Beaches’ worst lawn weeds, including sedges, dollarweed, and doveweed, thrive in constantly wet soil. As the rainy season ends, many irrigation systems keep running on summer schedules.

Here is what we have found works best. Adjust irrigation for the dry season based on how the lawn looks, water early in the morning, follow your local watering day restrictions, and make sure your rain sensor works. Deeper, less frequent watering encourages deeper roots and discourages shallow-rooted weeds.

Post-Emergent Control

Post-emergent herbicides target weeds that are already growing. St. Augustine is sensitive to some herbicides that are safe on other grasses. Always read the label carefully, choose products labeled for your grass type and the specific weeds you are targeting, and follow temperature restrictions.

In lawns with scattered weeds, spot treating saves product and reduces stress on the grass. Broadcast treatments make sense when weeds are widespread.

Pre-Emergent Timing in South Florida

Pre-emergent herbicides stop many weed seeds from emerging. In South Florida, where some weeds germinate much of the year, pre-emergents are often timed ahead of the main germination periods for weeds like crabgrass and goosegrass, commonly in late winter and again in fall. They do not control sedges or perennial weeds that spread by runners or tubers. Most also prevent grass seed and can affect new sod or plugs, so timing matters if you plan repairs.

A Thick Lawn Is the Best Defense

Weeds fill empty space. Mow Floratam St. Augustine at around three and a half to four inches, and zoysia and Bahia at the heights recommended for them. Avoid scalping. Feed moderately in fall, following your city’s ordinance, so the lawn stays dense through the dry season.

Chinch Bug Damage Leaves Room for Weeds

In St. Augustine, chinch bug damage often leaves thin, brown areas that weeds quickly fill. Keeping chinch bugs in check, especially in hot, sunny areas near pavement, helps prevent weed problems.

Shade Under Palms and Trees

Many Palm Beach landscapes have palms, sea grapes, oaks, and other trees. St. Augustine thins in heavy shade, especially Floratam, which is less shade-tolerant than some varieties. Weeds move into those thin areas. Shade-tolerant St. Augustine varieties, thinning canopies where practical, or using mulched beds in the deepest shade can help.

Weed and Feed Products

Weed and feed products are convenient, but they rarely line up well with local timing and rules. The fertilizer half may be restricted in some cities during certain months, and the herbicide half may not target the weeds you have. Treating weeds and feeding the lawn as separate steps usually works better.

Hand Pulling Has Limits

Pulling a few weeds by hand works for annual broadleaf weeds caught early. It rarely works for sedges and dollarweed, since nutsedge spreads from underground tubers and dollarweed from runners. Pieces left behind regrow quickly, often making the problem look worse a few weeks later.

Beds and Edges

Weeds in landscape beds next to the lawn spread seed and runners into the turf. Keeping beds mulched and weeded, with a clean edge, reduces that pressure.

Keep It Away From Water

Many properties border canals, lakes, and the Intracoastal. Keep herbicides and fertilizers well away from the water’s edge and storm drains, and avoid spraying on windy days near seawalls and docks.

Seasonal Residents

If you split your time between the Palm Beaches and somewhere else, fall is an especially good time to set the lawn up before you arrive or leave. Adjusting irrigation controllers before you go and scheduling weed control while you are away keeps the lawn from getting ahead of you.

Mowing Frequency

Letting St. Augustine grow very tall and then cutting it back hard stresses the grass and opens gaps for weeds. Mowing regularly at the right height, removing no more than about a third of the blade at a time, keeps the canopy dense.

Keep Records

Note which weeds show up where. That record helps make next year’s treatments more targeted and shows whether irrigation changes are working.

What to Expect

Weed control in South Florida is ongoing. Sedges and dollarweed often take more than one treatment, especially if watering habits do not change. Each season of consistent care makes the lawn cleaner.

What a Clean Season Looks Like

Imagine your lawn in February, with guests in town. The sedge along the driveway is gone, the dollarweed in the backyard has shrunk since the sprinklers were cut back, and the Floratam is thick enough that new weeds have trouble finding room.

What to Do Next

This month, adjust irrigation for the dry season and water only in the morning, treat sedges, dollarweed, spurge, and other broadleaf weeds with products labeled safe for your grass type, keep mowing at the right height, and feed moderately according to your city’s ordinance. Set irrigation controllers before you travel.

If you would rather have someone else handle the timing decisions, product selection, and application for your Palm Beach lawn, we are here for that. Lawn Squad of The Palm Beaches serves homeowners across the Palm Beaches. Visit lawnsquad.com to request a free quote. Our VitaminLawn program is built for the grass types, soils, and weather patterns we deal with here.

Here is what to expect. We will look at your grass, talk through how your lawn handled this year, and explain what we would apply before winter and why. If your lawn does not need a late-season application, we will tell you that honestly.