St. Augustinegrass: Cultivar Guide and Complete Management for the Southeast
A note upfront: I run zoysia. I have no firsthand experience with St. Augustinegrass. Everything in this article is drawn from university extension research, primarily UF/IFAS (the definitive source for SA), Texas A&M, LSU AgCenter, and Clemson HGIC, not from my own lawn. Regional recommendations differ meaningfully between Florida, the Gulf Coast, and the Carolinas, so treat this as a research-backed starting point and then check your own state’s extension office for local timing, rates, and cultivar availability. Links to the primary sources are at the bottom.
Most people who end up with St. Augustinegrass didn’t choose it, they inherited it. You bought the house, there was SA in the yard, and you’ve been applying whatever lawn care instincts you brought from somewhere else. If the lawn is struggling, that’s usually why.
St. Augustinegrass (Stenotaphrum secundatum) is a higher-maintenance grass relative to zoysia or centipede. It has a higher nitrogen demand, it’s the preferred food source of the most destructive lawn pest in Florida, it can’t be started from seed, and it’s sensitive to the broadleaf herbicides that work fine on every other common warm-season grass. None of that makes it wrong for your site, in the right situation (coastal, Zone 8–10, warm and humid, decent shade) it’s genuinely the best fit. But “it’s everywhere around here” isn’t a management plan.
If you’re comparing SA to zoysia before making a choice, the cultivar breakdown for zoysia is at frugallawnguy.com/zoysia-cultivar-guide. This article is for people who already have SA, or who’ve decided that’s the grass for their site.
What to buy: Hi-Yield Atrazine, 32 oz (~$22.29) for winter weeds · Bifen I/T, quart (~$40.98) if chinch bugs are the problem. All picks and why.
What Makes St. Augustine Different
SA spreads by above-ground stolons only, no rhizomes. There are no seeded cultivars; commercial seed does not exist for St. Augustine. Every cultivar requires sod, plugs, or sprigs.
It is the most shade-tolerant warm-season grass available, but “shade-tolerant” has a floor. Even the best cultivars need 4–6 hours of direct sun daily. Below that, you’re managing decline, not turf.
Nitrogen demand is 2–6 lbs N per 1,000 sq ft per year depending on region (UF/IFAS LH010). It is the preferred food source of the southern chinch bug (Blissus insularis), the pest that kills SA lawns at scale across the Southeast.
The most common management mistake: applying 2,4-D. Most broadleaf weed killers, Ortho Weed B Gon and most generics, contain 2,4-D or dicamba, or both. Both injure SA: leaf curl, stem damage, dieback. Many product labels explicitly exclude St. Augustine. Read the grass species compatibility on every product before it touches an SA lawn. MSMA is off the table entirely, it’s been de-registered for home lawn use.
Cultivar Guide
Floratam
The default SA. Dominates the market because most sod farms produce it and it’s the cheapest pallet price. Released in 1973 with chinch bug resistance that UF/IFAS confirms has largely been lost over time. Coarse texture, dark green, requires 6+ hours direct sun, poor cold tolerance. Sensitive to atrazine above 85°F, do not apply in peak summer heat. Susceptible to gray leaf spot. Floratam can also contract Lethal Viral Necrosis in addition to the more common SA Decline virus.
Reasonable choice for deep south Florida with full sun and no chinch bug history. For anyone north of that, with shade, with chinch bug pressure, or looking for cold hardiness, better options exist.
Palmetto
Very good cold tolerance, very good shade tolerance, and among the best chinch bug resistance of any widely available standard cultivar (UF/IFAS EDIS Table 1). Medium texture, lighter green, mow at 3.5–4 inches. A reasonable all-around pick for most SA homeowners outside deep south Florida.
One correction to a common claim: research does not support Palmetto being more drought-tolerant than other standard cultivars. That claim circulates widely but isn’t backed by university extension data.
Seville
Very good shade tolerance, dense growth habit, mows at 2–2.5 inches (dwarf type). Trade-offs: thatch prone, shallow roots, susceptible to chinch bugs and sod webworms. Right for lawns with 3–4 hours of filtered sun in Zone 9 or warmer. Cold sensitivity rules it out at the upper end of SA’s range.
Raleigh
Released by NC State in 1980 specifically for cold hardiness, the standard choice for north and northwest Florida, lower coastal Georgia, anywhere SA is pushing its northern limits. Weaknesses: highly susceptible to gray leaf spot (iron supplementation can help with the summer yellowing), and it prefers heavier, lower-pH soils. Poor chinch bug resistance. Right call in Zone 8a–8b where cold winters are the binding constraint.
Viridian (formerly ProVista)
Rebranded by Scotts in 2025. Core trait: first glyphosate-tolerant turfgrass commercially available. Apply Roundup to kill weeds without killing the lawn. Grows at roughly half the rate of Floratam. Very good shade tolerance. Premium pricing and limited availability are real. Not a cost-sensitive recommendation.
Captiva
UF’s answer to Floratam’s lost chinch bug resistance. Best chinch bug resistance of any commercially available SA cultivar. Dwarf type, 2–3 inch mowing height, dark green, good cold and shade tolerance. Florida-focused production.
CitraBlue
UF/IFAS release from 2018. Blue-green color, denser growth, very good shade tolerance, better drought tolerance than Floratam and less disease than most standard cultivars per UF/IFAS data. Mow at 2–3 inches. The direction UF/IFAS has been pointing the market.
Quick Cultivar Reference
| Who you are | The pick | Primary reason |
|---|---|---|
| Default / replacing Floratam, good sun | Palmetto | Good all-around; cold, shade, chinch tolerance |
| Chronic chinch bug history, FL | Captiva | Best available chinch bug resistance |
| Significant shade, Zone 9+ | Seville | Fine texture, dense, very good shade |
| Cold concern, upper Gulf / north FL | Raleigh or Palmetto | Cold hardiness is the binding constraint |
| Want simpler weed management | Viridian | Glyphosate tolerance, slower growth, good shade |
| Want current UF genetics, FL | CitraBlue | Drought tolerance, shade, newer disease data |
| Budget, deep south FL, full sun | Floratam | Cheapest, most available |
Mowing and Fertility
Standard cultivars (Floratam, Raleigh, Palmetto, CitraBlue): maintain at 3.5–4 inches with a rotary mower. Dwarf cultivars (Seville, Captiva): 2–2.5 inches. Never remove more than one-third of the blade in a single pass. SA crowns don’t recover from a hard scalp the way bermuda does. Sharpen rotary blades regularly; dull blades shred the wide SA leaf and leave a brown cast.
For nitrogen: 2–4 lbs N per 1,000 sq ft in north Florida, 4–6 lbs in south Florida (UF/IFAS LH010). Gulf Coast Georgia and SC coastal, treat as north Florida. First application no earlier than mid-April.
Iron: SA on high-pH soils or alkaline irrigation water yellows from iron deficiency that looks like nitrogen deficiency. If you’ve applied nitrogen and the lawn is still yellow, chelated iron (Southern Ag Chelated Liquid Iron, ~$10–15 for 16 oz) as a foliar spray is the right next move. Raleigh is particularly prone to this in peak heat.
Chinch Bugs: The Primary Threat
Damage looks like irregular yellowing in hot, dry, full-sun areas, along sidewalks, adjacent to structures, spreading outward as the population moves to fresh grass. This distinguishes chinch bugs from take-all root rot (which appears first in shadier, wetter areas) and drought (which stresses the lawn more uniformly).
Flotation diagnostic: Remove both ends from a metal coffee can, push it 3 inches into the soil at the margin of a yellowing area, fill with water for 5 minutes. Chinch bugs float to the surface. Run at multiple spots around the damage edge.
Treatment: Southern chinch bugs (Blissus insularis) have documented resistance to both pyrethroids and neonicotinoids. Rotate modes of action, do not spray the same chemistry twice in a row. Generic bifenthrin concentrate (Bifen IT, ~$20–30 for 32 oz) is a reasonable starting point. If it doesn’t hold, rotate to a different mode of action. Imidacloprid’s systemic action can handle some resistant populations but resistance is documented there too. Check your state extension’s current resistance guidance before selecting a product.
Buy it: Bifen IT (bifenthrin 7.9%) 32 ozaround $20–30.
Not sure if it’s chinch bugs, drought, or something else? The triage article walks through how to tell them apart.
Gray Leaf Spot
Gray leaf spot (Pyricularia grisea) is a summer disease that hits new growth hardest. Typically after heavy fertilization or during humid stretches. It shows as small tan or gray lesions with dark borders on leaves and stems. Raleigh is highly susceptible. Floratam gets it too.
The main trigger is excess nitrogen in summer heat combined with drought stress or wet foliage at night. Avoid late-afternoon irrigation and hold back on N during peak summer if disease pressure is high.
Strobilurin fungicides (group 11. Azoxystrobin, pyraclostrobin) are the most effective chemical option. Under heavy pressure, tank-mix with a DMI fungicide (group 3. Propiconazole, myclobutanil) to broaden coverage and slow resistance development.
Take-All Root Rot and Other Diseases
Take-all root rot (TARR) is the most frequently misdiagnosed problem in SA lawns, called drought stress, called chinch bugs. The diagnostic tell: pull an infected stolon. Roots are short, black, and rotted. Chinch bugs leave roots intact; TARR destroys them.
TARR pressure increases when soil pH is at or above 6.5 and fertility is low. There are few effective homeowner fungicide options, cultural control is the primary defense.
Cultural treatment: 1 bale (3.8 cubic feet) of sphagnum peat moss per 1,000 sq ft. Sphagnum peat pH of ~4.4 suppresses the TARR pathogen directly. Texas A&M field research confirmed peat moss outperformed manure compost for TARR suppression. Caveat: alkaline municipal water in Florida gradually neutralizes the effect, reapply in spring. If you do apply a fungicide (azoxystrobin, propiconazole), it must be preventive, about one month before when your lawn historically shows symptoms. Curative applications after visible rot are limited in effectiveness.
SA Decline and Panicum Mosaic Virus: no cure for either. Both spread via contaminated mowers and sod. If you’re buying sod, verify it’s certified disease-free. Floratam can also contract Lethal Viral Necrosis. If symptoms look viral, mosaic pattern, mottled yellowing, stunting, the only real answer is removal and replanting with clean material.
Herbicides: What Works, What Damages, What’s Gone
Grassy-weed options for SA are limited. That makes a consistent pre-emergent program more important here than on most other warm-season grasses. Stopping weeds before germination is easier than removing them after.
Atrazine is the cornerstone selective herbicide for SA. Controls dollar weed, chickweed, clover, oxalis, spurge, and more. Consumer products (Hi-Yield Atrazine, ~$15–20 for 32 oz; Southern Ag Atrazine on St. Augustine Grass, ~$12–18) are general-use, no license required.
Do not apply atrazine above 85°F. Do not apply to drought-stressed grass. Both conditions increase injury risk significantly, particularly on Floratam.
2,4-D injures St. Augustine. Many product labels explicitly exclude it, but plenty of homeowners apply Weed B Gon or generic broadleaf killers without reading those exclusions. Check every label.
MSMA is de-registered for home lawn use. Do not use it.
Buy it: Hi-Yield Atrazine Weed Killer 32 ozaround $15–20.
Buy it: Southern Ag Atrazine St. Augustine Weed Killer 32 ozaround $12–18.
For timing guidance, this article covers the seasonal sequencing.
Top 3 Anti-Patterns
Scalping in spring. The instinct is to “get the lawn looking clean” after winter. SA crowns don’t recover from scalping the way bermuda does. Cut it hard in March and you’ve set the stage for a weak stand heading into peak chinch bug season. Keep it at the correct height year-round.
Applying weed-and-feed without checking compatibility. Many weed-and-feed products contain 2,4-D, which damages SA. Read the grass species label every single time, including on products you think you already know.
Overwatering in shade. The problem in a shaded area is usually light, not water. Adding irrigation to compensate for thin, stressed grass in shade increases TARR pressure without solving the underlying deficit. Address the light deficit first. Prune trees before you add water or re-sod.
Products Mentioned in This Article
- Bifen IT (bifenthrin 7.9%) 32 oz, Buy it · also on Amazon
- Hi-Yield Atrazine Weed Killer 32 oz, Buy it · also on Amazon
- Southern Ag Atrazine St. Augustine Weed Killer 32 oz, Buy it · also on Amazon
More retailer options will be added as we partner with additional suppliers.
Sources
- UF/IFAS EDIS ENH5/LH010, “St. Augustinegrass for Florida Lawns” (rev. Oct 2024), https://edis.ifas.ufl.edu/lh010
- Clemson Cooperative Extension HGIC 1211, “St. Augustinegrass”, https://hgic.clemson.edu/factsheet/st-augustinegrass/
- Texas A&M AgriLife Extension EHT-144, “St. Augustinegrass”, https://aggieturf.tamu.edu/wp-content/uploads/sites/24/StAugustine.pdf
- LSU AgCenter, St. Augustinegrass lawn care publications, https://www.lsuagcenter.com
This site uses affiliate links. They don’t change what I recommend. They keep the lights on here.
