If you live in Florida or another subtropical climate in the U.S., you’ve likely seen St. Augustinegrass. This thick-bladed grass, sometimes called St. Fungustine for its propensity to fungal disease, is ideal for coastal, subtropical regions. Under proper management, St. Augustine produces a beautiful, slightly open-canopied lawn that withstands moderate foot traffic and tolerates the most shade among any warm-season grass.
St. Augustine at a glance
Classification: Warm-season grass
Spreads by: Stolons
Shade tolerance: Moderate shade tolerance, among the highest of any warm-season grass; some cultivars more shade tolerant than others
Drought resistance: Moderate
Foot traffic tolerance: Moderate
Maintenance needs: Moderate to high mowing frequency
Mowing height: 2.5-4 inches (mow dwarf varieties from 2.5-3 inches; standard cultivars from 3-4 inches; mow tall in shade)
Potential for disease: Moderate to high
Soil pH: 6-7.5
Soil type: Tolerates many soil types; prefers moderately fertile and moist (not waterlogged) soils; not a highly drought-tolerant grass; doesn’t tolerate soil compaction
Other notes: Native to coastal areas across the world and prefers moist soils and mild winters; will thrive in more inland areas provided growing conditions are met; good salt tolerance; will go dormant during winter in all but the southernmost regions
What is St. Augustinegrass?
St. Augustinegrass is a popular warm-season turfgrass planted along most of the southern swath of the U.S. and Hawaii. This heat-loving, coastal grass is found from Texas east to the Carolinas, including Florida. It is used in some parts of central and southern California, as well.
St. Augustine lawns are prized for their wide blades, fast growth, and moderate shade tolerance. A healthy, well-maintained St. Augustine lawn gives an instant face-lift to your home and landscape. The downsides: Its moderate to fast rate of growth means you’ll need to mow often. In addition, St. Augustine prefers mild winters, so this coarse-bladed beauty has a limited range even in the warm-season grass zone.
Pros and cons of St. Augustinegrass
If you do live in a tropical zone where St. Augustine can grow, it doesn’t mean it’s the ideal grass for you. Check out these pros and cons to see if it is perfect for your yard.
Pros
✓ Heat-loving grass
✓ Moderate shade tolerance, among the best for warm-season grasses
✓ Suited for coastal areas; high salt tolerance
✓ Fast growth rate
✓ Available as sod, sprigs, or plugs
✓ One of the coarsest-bladed grasses
✓ Crowds out most weeds
Cons
✗ Needs mowing often
✗ Limited range due to low cold tolerance
✗ Susceptible to chinch bugs and fungal diseases
✗ Not available as seed
✗ Susceptible to thatch in if given too much fertilizer or water
✗ Growth habit is not exceptionally dense
How to establish St. Augustinegrass
St. Augustinegrass can be established via sod, sprigs, or plugs. Because there is no seed commercially available, you can establish St. Augustine nearly any time of year. In South Florida, spring, fall, and winter work fine. In areas to the north, spring or fall are generally best. For best results, avoid establishing this grass in cold or very hot weather.
After the sod, sprigs, or plugs are put down, water to keep the soil consistently moist, but not soaked. For the first week to 10 days, water multiple times per day. For the second and third week, apply ¼ to ½ inch of water once per day. After this, water two or three times per week at ¼ to ½ inch of water each time. The grass should be established three or four weeks after you plant. At that time, you can water as you would for an established lawn.
Finally, don’t fertilize until one to two months after you sod. You can begin to mow two to three weeks after planting.
How much does St. Augustinegrass cost?
St. Augustine sod: Costs between 30 to 80 cents per square foot
St. Augustine plugs: A 64-count of plug trays start at around $110 and go up from there, depending on the cultivar.
Caring for St. Augustinegrass
Mowing
Mowing heights vary by cultivar. Cut dwarf varieties at 2.5-3 inches; cut standard varieties at 3-4 inches. Here are a few other mowing tips to get you started:
- Follow the ⅓ Rule of Mowing: Never remove more than ⅓ of the grass blade at one time.
- Increase mowing heights if the grass is in the shade or during a drought.
- Keep the mower blades sharp to give a clean cut and avoid tearing the blade, which may encourage fungal disease.
- Leave the clippings on the lawn for a free fertilizer boost. Don’t worry: The clippings won’t contribute to thatch buildup if you mow regularly.
Water
St. Augustinegrass is widely used in coastal areas; therefore, it can take frequent rains. However, if you go through a stretch without any rain, like most grasses, wait until the ground is completely dry before you turn on the irrigation system. Or, if you see the grass fold, wilt, or lose its natural color, it may be time to water.
Pro Tip: Ensure your lawn has adequate potassium to strengthen its drought tolerance. Potassium also will help the lawn to grow deeper roots and increase its cold tolerance.
Fertilization
Plan to apply from 2-6 pounds of nitrogen per 1,000 square feet per year. The further south you live, the greater number of applications you’ll put down, hence the wider-than-normal range. Apply less fertilizer in shady areas and more in areas receiving full sun. Levels of organic matter and soil type also affect how much nitrogen you need to apply.
It’s recommended to do a soil test before you apply fertilizer so you don’t over or under apply. A soil test also will indicate your soil pH, which is key to helping the grass uptake the nutrients it needs. Finally, mulch your clippings back into the lawn for a free fertilizer treatment every time you mow.
Dethatching and aeration
St. Augustine is known for its tendency to develop thatch. High rates of water and fertilizer also contribute to this problem. Some thatch is good, but a thatch layer over 1 inch means it’s time to take action.
If you need to dethatch your St. Augustine lawn, rent a dethatching or verticutting machine anytime from spring to the middle of summer.
- Dethatch across the lawn north-south or east-west. Don’t go in all four directions.
- Rake the debris.
- Mow the lawn.
- Water the lawn to prevent the roots from dehydrating.
- Apply fertilizer one week after dethatching. Use ½ pound per 1,000 square feet. Water it in. This will help the grass recover.
Dethatching machines remove some of this excess layer of roots and stems (AKA thatch) and allow air and water to reach the soil surface again.
In addition to dethatching your St. Augustinegrass lawn, it may be prudent to aerate as well. If any of the following apply to your lawn, aeration can help:
- Heavy or compacted soil
- Frequent foot traffic
- The yard is mowed with a large, heavy mower or has vehicle traffic
Core aeration acts like a sauna for your lawn: It opens up the soil so that air, water, and nutrients flow more efficiently. After you aerate, topdress with compost to improve soil conditions over time.
Disease, insects, and weeds
Disease: Fungal diseases are common in St. Augustine. Here are a few you may encounter:
- Gray leaf spot
- Large patch
- Take-all root rot
Ask neighbors who have St. Augustine lawns if they’ve had any of these problems and what solutions they’ve tried. Fungal diseases can be controlled with fungicides, but it is important to maintain the lawn properly so these fungi aren’t encouraged by improper cultural practices.
Nematodes also may be an issue. Proper lawn care is the most cost-effective way to strengthen the grass roots against nematodes. Mow tall, irrigate only when the soil is dry, and maintain adequate potassium levels to encourage deeper rooting.
Insects: Here’s a short list of insects that are common to St. Augustine:
- Chinch bugs (the major lawn pest for St. Augustine)
- Cutworms
- Mole crickets
- Grass loopers
- Armyworms
- Webworms
- Grubs
Weeds: Think of it this way: If you have a weed problem, focus on strengthening the grass, not killing the weed. Proper cultural management (mowing, fertilizer, watering) is key to reducing weed problems from the start.
If you need to apply chemical products, first make sure that the product can be used on St. Augustine lawns as some chemicals aren’t suited for this grass. Pre-emergent crabgrass control can be applied in early spring when soils are 55 degrees or higher (check your state’s Extension bulletins or a soil temperature tracker for timing).
Post-emergent grassy and broadleaf control can be done as needed during the summer. Don’t spray during a drought or when outside temps rise above 85 degrees Fahrenheit to avoid damaging the grass.
There are organic pre- and post-emergents if you want to limit chemical use. And remember that a full, healthy lawn is your best defense against excessive weeds.
Some information taken from Fundamentals of Turfgrass Management, 5th ed. by Christians, Patton, and Law
If you think a St. Augustinegrass lawn may be right up your alley, contact one of our local lawn care professionals. They can help you select, install, and care for your grass so you can spend your free time doing what matters most.
Main Photo Credit: Jay Morgan | Flickr | CC BY-SA 2.0
