Walk through any subdivision in Palm Beach County and you’ll see lawns that look identical to the untrained eye. They’re not. The “St. Augustine” on one side of the street might be Floratam (a 1973 release that loves full sun and gets hammered by chinch bugs), while the neighbor’s is CitraBlue (a 2019 UF release that tolerates shade, resists disease, and produces excellent color on roughly half the nitrogen). The same homeowner can feed both lawns with the same bag of fertilizer and one will thrive while the other develops thatch, disease, or worse.

The eight cultivars covered below are the ones we encounter most often across Palm Beach County and the Treasure Coast: Floratam, Palmetto, and CitraBlue (St. Augustinegrass); Empire, Zeon, and CitraZoy (zoysiagrass); and Celebration and Bimini (bermudagrass). Each has a specific UF/IFAS-supported nitrogen target, mowing height, and cultivar-specific risk profile that should change how you fertilize. This guide is built to be the practical reference homeowners and property managers can actually use to match the program to the lawn, instead of the lawn to the program.

One quick prerequisite: if you haven’t already, our seasonal fertilizer guide covers what the N-P-K numbers mean, why South Florida soil changes the math, and how the Palm Beach County summer blackout (June 1 through September 30) reshapes the whole year. Everything below assumes that foundation.

Why cultivar changes the math

UF/IFAS publishes nitrogen ranges by species (2–6 lb N/1,000 sq ft/yr for St. Augustinegrass in South Florida, 2.5–4.5 for zoysiagrass, 5–7 for bermudagrass), and those ranges are the starting point. But the range is wide because cultivars within a species can sit at opposite ends of it. Three things drive the difference:

• Growth habit and density. A dense, dwarf cultivar grows less vertical leaf tissue per unit of nitrogen than a coarse, upright one, so it needs less feed to look full. Dense cultivars also build thatch faster when overfed, which is its own problem.
• Disease and insect pressure. Cultivars with strong genetics (CitraBlue’s disease resistance, Palmetto’s chinch bug resistance) don’t need extra nitrogen to push past damage. Cultivars without those defenses (Floratam, Empire’s large-patch vulnerability) get worse when you over-feed them, because soft, lush growth attracts the very pests they’re already prone to.
• Mowing height. Lower-cut grasses (Empire at 1.75 inches, bermuda at 1–2 inches, dwarf zoysias under 1 inch) require more frequent inputs to maintain density at that height. Higher-cut grasses (standard St. Augustines at 3.5–4 inches) need less because they retain more leaf area for photosynthesis.

The practical upshot: even within the same species, the right nitrogen ceiling can vary by 50 percent or more between cultivars. The table below is the quick reference, and the cultivar-by-cultivar sections that follow are where the real specifics live.

All 8 cultivars at a glance

This table summarizes the South Florida targets we work to for each of the eight cultivars. Specific ranges trace to UF/IFAS publications ENH5/LH010 (St. Augustinegrass), ENH11/LH011 (zoysiagrass), and ENH19/LH007 (bermudagrass), with adjustments based on recent UF research (Schiavon et al., 2021) showing that newer cultivars often perform well at the lower end of the published range.

St. Augustinegrass cultivars

St. Augustine is the dominant lawn grass across Palm Beach County, and the three cultivars below cover roughly 95 percent of what’s actually growing in residential landscapes here. The UF/IFAS South Florida range for St. Augustine is 2–6 lb N/1,000 sq ft/yr, but recent research suggests the newer cultivars perform well at or below the bottom of that range. Use the cultivar targets below, not the species ceiling.

Floratam

Released jointly by UF and Texas A&M in 1973, Floratam is still the most widely planted St. Augustine in Florida. It’s coarse-textured, dark green, and has poor cold and shade tolerance (it really wants at least six hours of direct sun). The chinch bug resistance it had at release has largely been lost, and Floratam is now the primary host for chinch bug damage across the county. It is also susceptible to Lethal Viral Necrosis (LVN) caused by sugarcane mosaic virus, which is widespread across southeast Florida and increasingly drives sod replacement decisions.

Fertilizer target: 3–5 lb N/1,000 sq ft/year, split across 3–4 applications. Mow at 3.5–4 inches. While UF/IFAS officially lists 4–6 lb N/yr as the South Florida range, recent four-year UF research (Schiavon et al., 2021) at the Fort Lauderdale REC found that Floratam maintained adequate quality on as little as 2.5 lb N/yr, and we recommend staying toward the lower end of the published range. A slow-release 15-0-15 is the workhorse product. Floratam is the cultivar most punished by quick-release nitrogen spikes: lush, soft growth is exactly what chinch bugs and gray leaf spot exploit, so a heavy 24-0-11 application followed by hot, humid weather is the textbook setup for a full pest outbreak.

Cultivar-specific cautions: Floratam is intolerant of atrazine herbicide above 85°F, so any weed-and-feed product applied in late spring or summer can damage it. It also lacks shade tolerance, so a Floratam lawn that’s slowly thinning under a maturing tree canopy is more likely a light problem than a fertility problem — adding more nitrogen will not fix it.

Palmetto

A 1988 Florida selection, Palmetto is technically a semi-dwarf St. Augustine with a shorter growth habit than Floratam, a finer (medium) texture, and a slightly lighter green color. UF/IFAS rates it very good for cold tolerance, very good for shade tolerance, and notably very good for chinch bug resistance — the only commercially available St. Augustine cultivar with that rating. That makes it the practical default for partial-shade properties and for owners who have lost a Floratam lawn to chinch bugs and don’t want to repeat the experience.

Fertilizer target: 2.5–4 lb N/1,000 sq ft/year, split across about 3 applications. Mow at 3–4 inches. Palmetto is a lighter feeder than Floratam, and that’s the most important programming difference. Its denser growth habit converts nitrogen into thatch more readily than Floratam does, and an overfertilized Palmetto lawn typically signals the problem with a spongy feel underfoot before any visible color change. A slow-release 15-0-15 is the right backbone product, but you should aim for the lower end of the rate range and skip applications if the lawn is already deep green.

Cultivar-specific cautions: the thatch tendency is the headline. Verticutting may be needed every 2–3 years on a Palmetto lawn that’s been on a generous fertility program. Palmetto can also yellow in summer heat more than Floratam does, but the fix is usually iron (chelated iron foliar, every 6 weeks during stress periods), not more nitrogen.

CitraBlue

The newest of the three, CitraBlue was developed at UF and released to the market in 2018–2019. It’s the only St. Augustine cultivar in Florida currently in an accredited sod certification program. The visual is distinctive: a blue-green color (hence the name), denser and more prostrate growth than Floratam, and a more uniform appearance. It’s rated very good for shade tolerance, and UF research shows it has better drought tolerance and notably better disease resistance than Floratam, Palmetto, and Raleigh.

Fertilizer target: 2.5–4 lb N/1,000 sq ft/year, split across about 3 applications. Mow at 2–3 inches (lower than other St. Augustines because of its prostrate habit). The Schiavon et al. four-year UF trial found that CitraBlue produced the highest turfgrass quality, color, and density of any St. Augustine cultivar tested, and that nitrogen rate had minimal effect on its performance — meaning it can be maintained at the lower end of the rate range without quality loss. This is the cultivar where we lean hardest on iron and biostimulants: it responds dramatically to iron applications, often producing color that rivals heavily-fed Floratam without forcing any new growth.

Cultivar-specific cautions: the dense, horizontal growth habit can drive thatch accumulation faster than Floratam, so over-fertilizing is still possible and the consequence still shows up first as thatch. Because CitraBlue is newer to the market, long-term performance data is still emerging, but everything to date supports a leaner, slower-release program than the older cultivars need.

Zoysiagrass cultivars

Zoysia is the second most common warm-season grass in Palm Beach County, particularly in newer high-end developments. It’s denser, finer-textured, and more wear-tolerant than St. Augustine, but it’s also slower to recover from damage, more prone to thatch, and notably susceptible to large patch disease — which is directly worsened by over-fertilization with soluble nitrogen.

The UF/IFAS South Florida zoysiagrass range is 2.5–4.5 lb N/1,000 sq ft/yr, and the official guidance is unambiguous on form: zoysia responds best to “spoon-feeding” (small quantities applied frequently) rather than larger, less-frequent doses, with potassium applied at rates equal to nitrogen.

Empire (Empire Turf, SS-500)

Empire is by a wide margin the most common zoysia in Florida. It’s a coarse-textured Zoysia japonica with a very dense growth habit, performs well on both sandy and clay soils, and has shade tolerance better than Meyer (the old standard) but not as strong as the fine-textured matrella cultivars. UF/IFAS describes its performance as good throughout the state, but flags it as susceptible to large patch — the single biggest disease threat to zoysia in our climate.

Fertilizer target: 2.5–4 lb N/1,000 sq ft/year, split across 3–4 applications. Mow at 1.75–2.5 inches. Apply potassium at rates roughly equal to nitrogen — a 15-0-15 analysis is the textbook fit for the same reasons it works on St. Augustine. The single most important programming rule for Empire is to avoid heavy nitrogen applications in early spring (before it’s fully greened up) and late fall, because both windows significantly increase the risk of large patch disease per UF/IFAS guidance.

Cultivar-specific cautions: Empire thatches quickly when over-fertilized — UF/IFAS specifically notes this and recommends keeping nitrogen at the lower end of the range as the primary thatch-prevention strategy. Verticutting every 1–2 years is typical. Watch the spring start: Empire is one of the last warm-season grasses to fully green up, and feeding while it’s still semi-dormant is wasted nitrogen at best and a disease trigger at worst.

Zeon

Zeon is a fine-textured Zoysia matrella, dark green, with very good shade tolerance and a manicured appearance that homeowners often describe as “carpet-like.” It’s popular on golf courses and high-end residential properties. UF/IFAS notes a relevant caveat: Zeon is “popular in many regions but is not as well adapted to Florida” as some other matrella cultivars, and it’s subject to dollar spot and large patch.

Fertilizer target: 2–3.5 lb N/1,000 sq ft/year, split across 3–4 applications. Mow at 0.5–2 inches (most residential Zeon installations sit at 1–1.5 inches with a sharp reel mower; rotary mowing above 2 inches can cause an uneven, scalped appearance). Zeon is a slightly lighter feeder than Empire because its finer texture and denser canopy convert nitrogen to thatch even faster. Potassium should match or exceed nitrogen — a 16-0-8 or 15-0-15 with at least 50 percent slow-release is the right call.

Cultivar-specific cautions: dollar spot disease can appear on Zeon when nitrogen is below optimal, and UF/IFAS notes this can be corrected with a light nitrogen application — useful to know because it means a Zeon lawn showing small, silver-dollar-sized circles often needs a small nutritional adjustment rather than a fungicide. Conversely, large patch (the bigger threat) shows up when nitrogen has been too high or applied at the wrong time. The window between under-feeding and over-feeding Zeon is narrower than most cultivars, which is exactly why spoon-feeding works.

CitraZoy

Released by UF in 2019, CitraZoy is a hybrid between a well-adapted Z. matrella and Z. japonica, with a medium-fine leaf texture that sits between Meyer and the matrella cultivars. UF/IFAS lists three standout characteristics: good wear tolerance, the best winter color retention of any zoysiagrass on the market, and — critically — no observed cases of large patch disease, which is the single biggest reason to consider it over Empire or Zeon. It will get leaf spot, but that’s a far more manageable problem.

Fertilizer target: 2.5–4 lb N/1,000 sq ft/year, split across 3–4 applications. Mow at 1–2 inches. CitraZoy’s standout winter color retention means it stays green longer in cool weather than other zoysias, which subtly changes the late-fall feeding strategy: a “winterizing” potassium-heavy application in late November still makes sense, but the lawn will continue using a small amount of nitrogen later into the season than Empire or Zeon would. Don’t push it — UF/IFAS guidance against late-fall nitrogen applies here too, since one of the biggest reasons CitraZoy is so attractive (large-patch resistance) shouldn’t be undermined by a late-season nitrogen flush.

Cultivar-specific cautions: production is still expanding, so sod is sometimes harder to source for repairs. Because it’s relatively new (released 2019), long-term data on a mature lawn under heavy use is still developing, but the disease-resistance profile alone is enough to make it the practical premium choice when a homeowner is willing to pay for a zoysia and large patch is a known concern in the neighborhood.

Bermudagrass cultivars

Bermuda is the hungriest of the three species we grow here, and the UF/IFAS South Florida range reflects that: 5–7 lb N/1,000 sq ft/yr. UF/IFAS itself notes those rates “are likely higher than needed for residential landscapes” and that further research is needed to refine them — meaning the published ceiling is a research-derived professional-grade target, and most home lawns and HOA common areas do fine at the lower end or slightly below. We typically program Celebration and Bimini lawns at 4–6 lb N/yr unless they’re functioning as a sports field or a heavily-trafficked area.

The other thing to know up front: bermuda grows very aggressively, so it’s prone to thatch buildup regardless of cultivar, and it has poor shade tolerance — a bermuda lawn that’s thinning under trees needs sun, not nitrogen.

Celebration

Celebration is an improved variety of common bermudagrass (not a hybrid), with a distinctive dark blue-green color, fine-medium leaf texture, and notably more shade tolerance than the older hybrid bermudas like Tifway 419 (though it still needs at least six hours of sun). UF/IFAS specifically calls out that Celebration “does not require as much maintenance as some of the other fine-textured bermudagrass cultivars,” which is the headline for any homeowner considering it: you get a fine-textured bermuda look without the full-time greenskeeper inputs.

Fertilizer target: 4–6 lb N/1,000 sq ft/year, split across 5–7 applications during the legal months. Mow at 1–2 inches. Rotary mowing works for Celebration (unlike some finer bermudas that need a reel mower) — UF/IFAS notes that mowing above 2 inches results in an uneven appearance. Spring application timing is the first lever: a 16-0-8 or 15-0-15 once the lawn is fully greened up, then four to six follow-up feedings spaced 4–6 weeks apart through the legal window. Drop to higher-potassium, lower-nitrogen analyses (8-0-16, 10-0-20) in late summer and fall to support cold tolerance heading into winter.

Cultivar-specific cautions: aggressive lateral growth means Celebration will invade flower beds, walkways, and neighboring zoysia or St. Augustine lawns within a single season — install with a deep edge and maintain it. Nematodes are the most serious pest of any bermuda in Florida; symptoms (general yellowing, thinning, slow recovery) are easy to misattribute to fertility, so a nematode assay through the UF/IFAS lab is a smart first step on a struggling bermuda lawn before adding nitrogen.

Bimini

Bimini is relatively new to the Florida market, and UF/IFAS describes its growth habit as intermediate between Celebration and the older hybrid cultivars like Tifway. Early evidence from the golf market supports its use on home lawns and athletic fields. Independent traffic-tolerance research from Oklahoma State has identified Bimini as among the most traffic-tolerant bermuda varieties, which is the headline characteristic driving its adoption.

Fertilizer target: 4–6 lb N/1,000 sq ft/year, split across 5–7 applications. Mow at 1–2 inches (similar to Celebration). The program looks much like Celebration’s: a balanced 15-0-15 or 16-0-8 with significant slow-release content, spaced 4–6 weeks apart through the legal feeding window, with a shift toward potassium-heavy products as fall approaches. Bimini’s improved cold tolerance and longer green-up window in South Florida mean it can productively use a light early-spring feeding slightly earlier than Celebration would tolerate, but the difference is measured in weeks, not months.

Cultivar-specific cautions: because Bimini is newer in Florida and large-scale Florida research is still limited, the published guidance is partly extrapolated from Celebration. The wear tolerance is real, and that’s the practical reason to choose it — Bimini holds up to athletic use, dog runs, and high-traffic commercial entries where most other grasses thin out. For a typical home lawn without heavy traffic, the lower-input case for Celebration is generally stronger.

The universal South Florida calendar

Cultivar drives the rates and the form, but the calendar is largely the same across all eight grasses in our region because the legal blackout dictates the windows. Every program we build in Palm Beach County moves through the same four phases:

The cultivar adjustments inside this framework are what separate a good program from a generic one. A Floratam lawn and a CitraZoy lawn might both receive a fall potassium application on November 15, but the bermuda lawn next door is on its sixth nitrogen feed of the year while the zoysia has had three. Same calendar, very different intensity.

The cultivar mistakes we see most

Across hundreds of Palm Beach County lawns, the same five or six fertility mistakes appear over and over. Most of them trace back to the same root cause: someone applied the program their last lawn needed, or the program the bag recommended, instead of the program this specific cultivar needs.

• Treating Palmetto and CitraBlue like Floratam. The older “4–6 lb N/yr South Florida St. Augustine” rule made sense for Floratam in the 1990s. Applied to Palmetto or CitraBlue, it creates thatch within two seasons. Both newer cultivars want roughly 2.5–4 lb N/yr — the lower end of the published range.
• Heavy nitrogen on Empire (or any zoysia) in early spring or late fall. This is the single biggest large-patch trigger UF/IFAS identifies. Push the spring feed until the lawn is fully greened up, and stop nitrogen by late October so the grass can harden before winter.
• Treating bermuda like a normal lawn. Celebration and Bimini genuinely need more nitrogen than the other six cultivars on this list — 4–6 lb N/yr split across 5–7 applications. Feeding them on a 3-application St. Augustine schedule starves them and invites weed invasion.
• Buying weed-and-feed for Floratam in summer. Atrazine, the herbicide in most St. Augustine weed-and-feed products, damages Floratam above 85°F. In South Florida, that’s most days from May through September — exactly when crabgrass shows up.
• Adding nitrogen to a yellowing Palmetto or Raleigh. On our alkaline coastal soils, the yellowing is more often iron deficiency than nitrogen deficiency. A chelated iron application solves it in 48–72 hours without forcing the soft growth that nitrogen would.
• Skipping the soil test, regardless of cultivar. Every recommendation above assumes a roughly average soil profile. The UF/IFAS Extension office at Mounts Botanical Garden runs a comprehensive soil test for around $20, and it’s the cheapest way to confirm whether your specific lawn needs phosphorus, more potassium, or a pH correction before you guess.
• Not knowing your cultivar. The most common mistake of all. If you’re not sure whether your lawn is Floratam or Palmetto, Empire or Zeon, the right move is a photo to your county Extension agent or a 5-minute on-site identification by a turf professional. Every rate and product on this page flows from that one piece of information.

The Granuly approach: chemical-free, cultivar-specific

Conventional lawn care across South Florida defaults to two assumptions: that every lawn in the species is the same, and that more synthetic input is better. Both are wrong, and both are how lawns end up over-fed, thatch-bound, and stuck on a chemical treadmill that gets more expensive and less effective every year.

Our chemical-free lawn care programs work from the opposite starting point. We identify your specific cultivar on the first visit, pull a soil sample for the UF/IFAS lab, and build a year-round program calibrated to that grass: the right N rate, the right potassium ratio, the right slow-release fraction, and the right cadence through the legal window. We rely on slow-release granular as the backbone, liquid iron and biostimulants (humic acid, kelp, fulvic acid) for precision color and soil health, and potassium plus micronutrients to carry the lawn through the blackout — without the synthetic pesticide and herbicide programs that traditional services bundle in by default.

The compound effect is the whole point. A CitraBlue lawn fed at 2.5 lb N/yr with a healthy soil biology will eventually look better than a Floratam lawn pushed to 6 lb N/yr with a quarterly chemical schedule — and it’ll get easier and cheaper to maintain every season instead of harder. The same logic applies whether you’re a single homeowner in Palm Beach Gardens or a property manager running 40 HOA acres in Jupiter.

If you’d like us to identify your cultivar, pull a soil test, and build a chemical-free fertilizer program calibrated to your specific grass and property, we offer a free on-site assessment for homeowners, HOAs, and commercial properties across Palm Beach County and the Treasure Coast. The right rate, in the right form, at the right time of year, for the actual grass you have. That’s the whole job.

FAQ

Brandon Seymour

Founder, Granuly

Brandon started Granuly with a clear goal: get lawns and landscapes to thrive with fewer chemical inputs. By combining organic, low-toxicity treatments with proactive cultural practices, he designs each program around plant biology, soil chemistry, and products he’d use in his own yard. Brandon holds multiple licenses with the Florida Department of Agriculture and Consumer Services, is Florida-Friendly certified, and is a proud member of the Palm Beach Chapter of the Florida Nursery, Growers and Landscape Association.