How to Get Rid of Dollarweed in a St. Augustine Lawn

To get rid of dollarweed in a St. Augustine lawn, fix the water problem first: dollarweed thrives in soggy, poorly drained soil, so cut back overwatering and correct drainage before you reach for any herbicide. Then spot-treat with a St. Augustine-safe post-emergent (atrazine, or a labeled 2,4-D/dicamba/MCPP blend) applied in cooler weather, and hand-pull small patches.

What is dollarweed, and why is it in my Central Florida lawn?

Dollarweed — also called pennywort — is one of the most common broadleaf weeds in Central Florida St. Augustine lawns. It spreads by seed, by rhizomes underground, and by tubers, which is why it seems to come back no matter how many times you pull it. But here's the part most homeowners miss: dollarweed is a symptom first and a weed second.

According to the University of Florida IFAS Extension (UF/IFAS), dollarweed flourishes in areas that stay too wet — from overwatering, poor drainage, a leaky irrigation head, or a low spot that never fully dries out. If you have a healthy, properly watered St. Augustine lawn, dollarweed struggles to get a foothold. If you have a soggy one, dollarweed moves in and takes over. That means the single most effective thing you can do is dry the area out. Spray all you want, but if the ground stays wet, the weed comes right back.

How do I identify dollarweed (and not confuse it with dichondra)?

Correct ID matters, because the plant dollarweed is most often confused with — dichondra — looks similar from a distance but is treated differently.

Dollarweed has:

• Round, coin-like leaves — bright green, roughly the size of a quarter to a silver dollar (hence the name)
• *A stem attached to the center of the leaf*, so the leaf looks like a tiny umbrella or lily pad
• Scalloped or slightly wavy edges
• A tendency to appear in wet, low, or overwatered patches first

Dichondra, by contrast, has kidney- or heart-shaped leaves with the stem attached at a notch on the edge of the leaf, not the center. The quick field test: pick a leaf and look at where the stem meets it. Center = dollarweed. Edge notch = dichondra. Getting this right saves you from mistreating the wrong plant.

Step 1: Fix the water problem (this is the real fix)

Before any herbicide, address why the dollarweed is there. This step alone will do more long-term good than a season of spraying.

Audit your irrigation. Central Florida lawns are frequently overwatered. UF/IFAS guidance is to water deep and infrequent — about 3/4 inch per application — rather than a little bit every day. Daily light watering keeps the surface constantly damp, which is exactly what dollarweed wants. Check that you're following your local watering-day rules and not running the system more than needed. If you're not sure how many days a week you're allowed to water, our Central Florida watering days guide for 2026 breaks down the Orange County schedule and how Osceola County (Toho Water Authority / City of St. Cloud) differs.

Find the wet spot. Walk the lawn a few hours after irrigation or rain. Where is it still squishy? Common culprits:

• A broken or misaligned sprinkler head dumping extra water in one zone
• A low area that collects runoff and never drains
• Downspouts discharging onto the turf
• Compacted or clay-heavy soil holding water at the surface

Improve drainage. Regrade low spots, redirect downspouts, and consider a French drain for chronically wet areas. On compacted soil, core aeration helps water move down instead of pooling on top.

Mow at the right height. Tall, healthy St. Augustine shades the soil and crowds out weeds. Keep St. Augustine at 3.5–4 inches and never remove more than 1/3 of the blade at once. Scalping the lawn opens gaps that dollarweed happily fills. A denser lawn is your best long-term weed control — see our complete lawn mowing guide for Florida for height and frequency specifics.

If you fix the water and the dollarweed still lingers, then move to treatment. Chemicals are step two, not step one.

Step 2: Treating dollarweed safely in St. Augustine

St. Augustine grass is sensitive, so product choice and timing are everything. Using the wrong herbicide — or the right one in the wrong conditions — can burn or kill your turf.

Hand-pull small patches

For a few plants or a small patch, hand-pulling works — but you have to get the rhizomes and tubers, not just the leaves. Pulling the tops off leaves the underground parts to regrow. Loosen the soil (easier when it's slightly moist) and lift out as much of the root system as you can. For a handful of plants, this is often all you need, and it avoids any chemical on the lawn.

Post-emergent herbicides for St. Augustine

For larger infestations, use a post-emergent labeled for St. Augustine grass. The two main St. Augustine-safe options for dollarweed are:

• Atrazine — widely used on St. Augustine and effective on dollarweed and many broadleaf weeds. It works both as a post-emergent and gives some pre-emergent activity.
• Three-way broadleaf blends (2,4-D + dicamba + MCPP) specifically labeled for St. Augustine — these can control dollarweed, but St. Augustine tolerates them only within a narrow rate and temperature window. Read the label; some general-purpose "weed & feed" broadleaf products are not St. Augustine-safe and will damage the lawn.

Whichever you choose, follow these rules:

1. Never spray in summer heat. Applying these products when temperatures are high — roughly above the mid-80s°F, which is most of a Central Florida summer — can burn St. Augustine. Treat in the cooler parts of the year or a cool stretch, in the morning, out of intense sun.
2. Read and follow the label exactly. The label is the law: it sets the rate, temperature ceiling, and how many applications are allowed. Overdosing St. Augustine to "hit the weed harder" backfires.
3. Two lighter applications beat one heavy one. Dollarweed's waxy leaf sheds spray, so a spreader-sticker (surfactant) helps, and a repeat application 2–4 weeks later often finishes the job better than a single heavy dose.
4. Don't mow right before or after. Give the weed intact leaf surface to absorb the herbicide.

What about the summer fertilizer ban and the heat?

This is where honesty matters. Central Florida's peak dollarweed season — the wet, warm rainy months — is exactly when you can't comfortably treat it, for two reasons:

• Heat. Summer temperatures make St. Augustine-safe herbicides risky, as noted above.
• The fertilizer blackout. Many Central Florida counties and municipalities — including Orange County and several local governments — enforce a summer fertilizer blackout (commonly June 1–September 30) banning nitrogen and phosphorus to protect waterways. Herbicides are not fertilizer, so the blackout doesn't ban weed control itself, but it does mean you shouldn't be pushing growth with a "weed & feed" that contains N or P during the ban. Check your specific county/city ordinance and the product label. Our Florida summer fertilizer ban guide explains what's allowed (iron for green-up, potassium, slow-release/no-phosphorus products) and what isn't.

The practical takeaway: use the summer months to fix the water problem (irrigation, drainage, mowing height) and hand-pull as needed, then do your chemical treatment in the cooler weather when both the heat risk and the fertilizer timing work in your favor. This is a case where patience and drainage genuinely beat spraying.

A simple year-round game plan

1. Now (any season): Find and fix the wet spot. Adjust irrigation to deep-and-infrequent, repair heads, improve drainage, raise your mowing height.
2. Small patches: Hand-pull, roots and all.
3. Cooler weather: Spot-treat remaining dollarweed with a St. Augustine-labeled post-emergent (atrazine or a labeled 2,4-D/dicamba/MCPP blend), per label, in the morning, out of the heat.
4. Repeat if needed: A second application a few weeks later cleans up survivors.
5. Keep it dense: A thick, correctly watered, properly mowed St. Augustine lawn is the best defense against dollarweed coming back.

When should you call a professional?

DIY is completely reasonable for a small patch and a straightforward wet spot — pull the weeds, fix the sprinkler, raise the mower, done. Call a pro when: the dollarweed keeps returning despite your best drainage efforts, the infestation covers a large share of the lawn, you're unsure which St. Augustine-safe product and rate to use, or you'd rather not risk burning the turf with a summer misapplication. A licensed applicator can dial in the right product and timing and diagnose drainage issues you might miss. If you also suspect insect damage in the same thin, stressed areas, it's worth ruling out chinch bugs in St. Augustine, which love the same weakened turf.

Get honest help with your Central Florida lawn

Dollarweed is beatable, but only if you treat the cause — water — before the symptom. If you'd rather have someone diagnose the wet spots and handle safe weed control for you, ProV Lawn Care & Landscape has served Central Florida since 2018. We offer transparent, no-contract pricing, the same crew every visit, and a trilingual team (English, Spanish, and Portuguese). Ask us about our fertilization and weed control service, or request a free estimate — no pressure, just honest, local lawn care for St. Cloud, Kissimmee, Lake Nona, Southeast Orlando, and Apopka.