What Is St. Augustine Grass? (Cultivar ID Guide)
St. Augustinegrass is a warm-season lawn grass, Stenotaphrum secundatum, that spreads by above-ground runners called stolons. Floratam, Raleigh, Palmetto, Seville, and CitraBlue are common cultivars. Their color and blade shape offer useful clues, but no single visual trait proves a cultivar. For certainty, check the sod records or request a lab test.
A common mistake is to name a cultivar from one clue, such as a blue-green color or a broad leaf. Yet sunlight, mowing, soil, and stress can all change how grass looks. That can lead to a wrong diagnosis or an unsuitable choice for a new lawn.
I compare several healthy areas and look at more than leaf color. The guide below explains what to check, how common cultivars differ, and when visual identification is not enough.
What St. Augustinegrass is and how it grows
St. Augustinegrass is a warm-season turfgrass grown mainly in warm regions. Its broad leaves grow from creeping stems called stolons, which spread across the soil and can root at points along the stem. This growth habit helps you recognize the grass, but it does not identify the cultivar by itself.
A cultivar is a selected type of a plant with traits people value, such as leaf texture or cold tolerance. St. Augustinegrass is often installed as sod or plugs. It is not usually identified by seed in a home lawn.
Stolons are a useful first clue: look for thick, above-ground runners that connect shoots and leaves. Then inspect several healthy spots. A shaded strip, a dry patch, or recently mowed grass may look different from the rest of the lawn.
Cultivar names matter because types can differ in appearance and performance. But descriptions are guides, not guarantees. Local conditions and care affect how each cultivar grows.
How to identify common St. Augustinegrass cultivars
Cultivar identification means comparing a lawn with documented traits of named types. Blade width, growth habit, color, and site conditions can narrow the options. Because these traits overlap, treat a visual match as a likely identification, not proof, unless records or a lab test confirm it.
The table summarizes useful field clues. These are relative descriptions, not fixed measurements. Compare grass growing under similar conditions, and do not identify a cultivar from color or one leaf alone.
| Cultivar | Common visual clues | Site or performance clues | Identification caution |
|---|---|---|---|
| Floratam | Coarse, broad blades; vigorous, more open growth | Generally performs best in sun; relatively cold-sensitive | Shade, stress, and mowing can change its look |
| Raleigh | Medium-coarse texture | Selected for better cold tolerance than Floratam; used in colder parts of the St. Augustine range | “Better cold tolerance” does not mean immune to cold injury |
| Palmetto | Softer, finer-looking foliage; more compact appearance than Floratam | Marketed for improved shade and cold performance | Still needs adequate light; shade can thin the lawn |
| Seville | Relatively fine texture and lower-growing habit | Often chosen when a finer appearance is desired | Fine texture alone does not confirm the cultivar |
| CitraBlue | Blue-green cast, medium texture, relatively dense growth | Color and density can be useful clues | Color changes with light, nutrition, and mowing |
Read the whole plant, not just the blade
Blade width describes how broad or narrow a leaf looks. Growth habit describes how the lawn fills space, including how dense the shoots appear and how stolons spread. Both can help you compare cultivars, but neither is a stand-alone test.
Look across several healthy areas and note blade width, color, density, and stolon form. Also note sun and shade exposure, recent mowing, and any cold or pest damage. Record what you see before mowing, since a fresh cut can make texture harder to judge.
Use site conditions as supporting clues
Site conditions help explain why a lawn looks a certain way. A sunny, hot area may show stress that a shaded area does not, while cold damage can change color and density. These differences can make one lawn appear to have several cultivars when it may be one cultivar growing under different conditions.
Compare areas with similar light and care first. If the lawn has recently been damaged, wait for healthy growth before making a visual comparison. Do not assume a cultivar is present just because the site seems suited to it.
A step-by-step field identification check
A field check is a careful comparison of healthy grass in several parts of the lawn. It helps you narrow down likely cultivars without relying on one striking feature. Use it before a renovation or treatment decision, but confirm the name through records or testing if the result matters.
- Choose representative areas. Check several healthy spots, including areas with different sun exposure. Avoid basing the ID on a bare, diseased, or recently damaged patch.
- Inspect the leaves. Compare blade width, softness, and color. Use more than one leaf and check plants that are not covered in clippings.
- Look at the growth. Note whether the lawn appears dense or open, and inspect the above-ground stolons. Do not pull up large areas just to find a runner.
- Record conditions. Write down shade, recent mowing, irrigation, cold damage, and any visible pest or disease symptoms.
- Compare descriptions. Use the table to identify possible matches, not a final answer.
- Check the source. Ask the sod supplier, installer, or previous owner for the cultivar name and documentation. Records tied to the lawn are more useful than a label based only on appearance.
If a cultivar name will guide a major renovation or treatment choice, ask a local extension service or qualified turf professional about confirmation. A laboratory DNA test may help when certainty is needed. Availability and testing methods can vary, so ask what sample and documentation the lab requires.
Practical lawn scenarios: applying the ID clues
These scenarios show how to use cultivar descriptions in a real lawn. They are examples, not reports of specific installations. A site clue can guide your next check, but it cannot establish a cultivar on its own.
Sunny lawn with broad, coarse leaves
Broad blades and vigorous, open growth may fit Floratam. If the same lawn also has cold-damaged areas, that history is worth recording because Floratam is relatively cold-sensitive. Still, do not identify it from those traits alone; compare healthy growth and check the sod records.
Shaded lawn with a finer look
A softer, finer-looking, compact lawn may fit Palmetto, while a relatively fine, lower-growing lawn may fit Seville. Shade can also reduce density, however, and mowing can change the apparent texture. Compare leaves and growth across healthy areas, and confirm the source before using the name to plan a replacement.
Lawn with a blue-green cast
CitraBlue may show a blue-green cast and dense growth. But color shifts with light, nutrition, and mowing, so it is not a reliable single test. Compare the lawn’s texture and growth as well, then look for supplier records if the cultivar name affects your decision.
Mowing and care while you assess the lawn
Care affects the traits you use for identification. A clean, even cut makes blade texture easier to compare, while scalping or ragged cuts can distort the lawn’s appearance. Mowing height should suit the cultivar and local guidance, so do not use a low setting just to make identification easier.
For many St. Augustinegrass lawns, a general mowing range is about 2.5–4 inches (6.4–10.2 cm). Check local extension advice and cultivar recommendations. Dwarf or compact types may tolerate a lower height only within their specific guidance; do not assume every cultivar does.
Remove no more than one-third of the leaf blade at a time. If the lawn has grown too tall, raise the deck and reduce the height over more than one mowing. A sharp, balanced blade and an even deck cut matter more for a clean result than a particular mower engine size.
Before mowing, check the guards, blade condition, deck height, and discharge direction. Clear toys, stones, and debris from the work area. Keep people and pets clear, and wear eye protection and closed-toe footwear. Stop the mower before clearing a clog or inspecting the blade.
After mowing, collect clippings if they clump or cover the turf. Clean and store the mower as its maker directs, and protect cutting parts from corrosion. Avoid aggressive scalping before cold weather; follow local guidance for seasonal care.
Common misidentification risks and next steps
Misidentification happens when a visible symptom is mistaken for a cultivar trait. Color, density, and blade size can all shift with growing conditions. Pest injury can also resemble drought stress, so check the lawn’s health before drawing conclusions from its appearance.
Chinch-bug injury can look like drought damage, especially in hot, sunny areas. Before adding water or fertilizer, inspect the boundary between damaged and healthy grass for insects. Excess irrigation or fertilizer without a diagnosis can waste inputs or make problems worse. Ask a local extension service or qualified turf professional if you cannot confirm the cause.
Cultivar names do not guarantee pest resistance or performance. Climate, pest populations, maintenance, and plant condition all matter. If the lawn’s condition is changing, diagnose the problem first rather than applying a pesticide or fertilizer based on a suspected cultivar.
The practical next step is to keep a short record: where you inspected, what the leaves and stolons looked like, and what conditions affected those areas. Pair that record with sod or supplier documentation. Seek professional or lab confirmation when an uncertain cultivar ID could affect a major renovation or treatment.
Frequently asked questions
These answers cover common questions about St. Augustinegrass and cultivar identification. They distinguish what you can reasonably observe from what needs records or testing. If a cultivar name will affect a major decision, use the visual clues to narrow the options, then seek confirmation.
Is St. Augustinegrass the same as Stenotaphrum secundatum?
Yes. Stenotaphrum secundatum is the scientific name for St. Augustinegrass, a warm-season turfgrass that spreads by above-ground stolons.
Can I identify a St. Augustine cultivar by color alone?
No. Color can change with light, nutrition, mowing, and stress. Use it as one clue alongside blade texture, growth habit, and site conditions.
Which St. Augustine cultivar has the broadest blades?
Floratam is commonly described as coarse with broad blades. Blade width alone does not prove that a lawn is Floratam.
Which cultivar is more cold-tolerant, Floratam or Raleigh?
Raleigh was selected for better cold tolerance than Floratam. This is a relative comparison, not a guarantee against cold damage.
Is Palmetto suitable for deep shade?
Palmetto is marketed for improved shade performance, but it still needs adequate light. A thin lawn in deep shade is not proof that the cultivar is wrong.
Does CitraBlue always look blue-green?
No. CitraBlue may have a blue-green cast, but color varies with light, nutrition, mowing, and plant condition.
What is the usual mowing height for St. Augustinegrass?
A general range is about 2.5–4 inches (6.4–10.2 cm). Follow local guidance and the cultivar’s recommendations, especially for compact types.
How can I confirm a cultivar if appearance is uncertain?
Check the sod supplier’s records or ask a local extension service or turf professional. A laboratory DNA test may be an option when certainty matters.
Can drought or insects make cultivar identification harder?
Yes. Drought, chinch-bug injury, cold damage, and disease can alter color and density. Diagnose visible damage before using it as an identification clue.
(This article was written by one of our staff writers, Evan Bradley. Visit our Meet the Team page.)
