Settle in for St. Augustine grass 101
St. Augustine grass is a warm-season blue-green grass that most commonly comes as turf or plugs instead of in seed form. But is it right for your yard? It depends on your USDA hardiness zone and your soil conditions. Let’s review everything you need to know about St. Augustine grass before adding it to your lawn.
What Is St. Augustine Grass?
St. Augustine grass is a moderately drought-tolerant warm-season grass that's popular in subtropical and humid states like Florida. This compact grass likes well-drained soil but isn't particularly fussy about soil type.
St. Augustine grass is the most popular warm-season turf for Southern U.S. states. It's also a popular choice for waterfront areas in warm locations because it's salt-tolerant, unlike many other warm-season grasses.
It requires moderate maintenance in its preferred climates and growing conditions. Outside of these ideal conditions, this grass is pretty high maintenance.
St. Augustine grass has broad, flat, dark green to blue blades. It forms a deep, dense mat that crowds out weeds and makes it fairly easy to get a green lawn without resorting to chemical weed killers.
What Does St. Augustine Grass Look Like?
St. Augustine grass is a dense grass with wide, flat blades often found in marshes, lagoons, shorelines, and other areas with high moisture. It can range from bluish-green to emerald or dark green in color. With the help of above-ground stolons—commonly called “runners”— it self-spreads and forms thick, carpet-like mats of sod.
Pros and Cons of St. Augustine Grass
St. Augustine grass won’t work for every yard, but it offers some perks that make it ideal for the right place. These are the key benefits and drawbacks of growing St. Augustine grass.
Pros of St. Augustine Grass
High tolerance for heat and humidity
Tolerant of partial shade
Grows more quickly than many other types of grasses
Requires infrequent mowing
Stays green year-round in temperatures of 60 degrees Fahrenheit or higher
Easy to propagate from sod
Thick, sodded Augustine grass doesn’t give weeds room to grow
Tolerant of salty and sandy soil conditions; ideal for coastal locations
Cons of St. Augustine Grass
Low cold tolerance
Can't withstand long periods of drought
Not green in winter
Needs a heavier fertilization regimen
Does not reproduce by seed; requires grass or plug
Can’t handle heavy foot traffic
Requires well-drained soil to avoid dying off or developing fungal infections
Prone to insects and disease
Types of St. Augustine Grass
This species has several preferred cultivars that are disease and insect-resistant, less sensitive to cold, have better color, and are tough enough to withstand more foot traffic. Here are more details of some of the most common cultivars to help determine which could be the best fit for your yard.
Floratine St. Augustine grass has a darker color, narrower blades, and a finer texture than common St. Augustine grass. It also tolerates cold temperatures better than other varieties and requires less mowing.
Floratam St. Augustine grass was developed to resist the viral infection St. Augustine Decline (SAD). It has little to no shade or cold tolerance, so it’s best for sunny locations that are warm year-round.
Bitterblue St. Augustine grass has a darker blue-green color and a coarser texture than common varieties. It also has improved tolerance to cold and shade. However, it is not resistant to chinch bugs and is more vulnerable to weeds than other types, meaning you’ll likely spend more time killing and preventing weeds.
This type of St. Augustine grass has a soft, fine texture and is resistant to chinch bug infestations. However, it is less cold-tolerant than other varieties.
Sapphire St. Augustine grass has brilliant coloration with dark blue-green leaves and purple stolons. It also has rapid lateral growth, so it can spread quickly and establish faster than other varieties.
Delta shade is a decently shade-tolerant cultivar of St. Augustine grass. However, it’s not as shade-tolerant as dwarf varieties.
Amerishade is a dwarf cultivar of St. Augustine grass that has the highest shade tolerance of all the varieties. It has small blades and a medium-to-coarse texture. Since it was developed for shade tolerance, it’s not suitable for areas with full sun.
Delmar is another dwarf cultivar of St. Augustine grass that has a brilliant emerald green color and short, medium-textured blades. It is one of the most cold-tolerant varieties and is relatively low-maintenance.
Captiva is a dwarf cultivar of St. Augustine grass that was developed by the University of Florida for resistance to southern beetles. Also, thanks to its dwarf profile, it requires less mowing.
Is St. Augustine Grass Good for Lawns?
Yes, in the right areas, St. Augustine grass is a great choice for lawns. In Florida, California, Texas, Hawaii, and other subtropical states, St. Augustine grass is the most popular type of grass for yards. However, in the driest areas, Bermuda grass is a better option, as it's more drought tolerant.
How to Grow St. Augustine Grass
While growing St. Augustine grass is pretty easy, there are some basic steps you need to follow to get a healthy green lawn:
Clear the area of weeds, dead grass, and debris.
Use a tiller or a rake to lightly dig over and loosen the bare soil.
Water the soil.
Lay down the sod or dig holes and plant your pieces of sod (also called plugs) about one to two feet apart.
Water lightly again.
Continue watering as needed to keep the soil moist as it grows.
Add mulch, fertilizer, or compost every 6 to 8 weeks.
When to Plant St. Augustine Grass
Plant your sod or plugs roughly three months before the first predicted frost in your hardiness zone. Or, if you don't typically get winter frosts, plant the grass in late spring to mid-summer.
To survive low winter temperatures, your grass needs to get established first, hence the need to plant three months before a frost.
How To Care for St. Augustine Lawns
St. Augustine grass is hardy and low-maintenance in some aspects, but it’s still important to provide it with the ideal light, water, and soil conditions. Here are the main things to keep in mind when caring for your St. Augustine grass.
St. Augustine grass likes full sun but can tolerate some shade, unlike most sun-loving grass varieties. Still, for optimal results, it’s always better to plant it in a full-sun area.
St. Augustine grass needs well-draining soil in order to thrive and avoid fungal disease. Loamy garden soil is ideal.
Keep the soil evenly moist for best results. St. Augustine grass tolerates a wide range of soils and is moderately drought-tolerant once rooted, but stays healthiest when it receives a healthy amount of watering.
St. Augustine grass tolerates heat and humidity well, making it perfect for hot to moderate climates. It’s not very tolerant to cold, so it should only be planted in areas with mild winters.
When to Fertilize St. Augustine Grass
After the initial fertilization, when you install the grass, don't be too impatient to do it again. Wait until it's well-established, then apply a high-nitrogen all-purpose fertilizer.
For established lawns, fertilize for the first time during the growing season once the grass is actively growing and has turned completely green. If you do it sooner, the grass can't process the fertilizer effectively, and you can end up causing burned patches that need reseeding or replacing.
After the first feeding, depending on your soil conditions and the type of fertilizer you use, you can fertilize every six to eight weeks to maintain peak health.
How to Water St. Augustine Grass
Watering grass is easy, regardless of species or cultivar. With a new lawn, water sod and plugs lightly daily for the first couple of weeks, then move to watering deeper but less frequently, at around three times a week.
Once mature and of suitable mowing height, you can treat your new grass like a regular, mature lawn. Encourage strength and independence by helping the grass grow deep, strong roots. This method helps the grass become more drought-tolerant and self-sufficient for nutrients. You achieve this by only watering once every two weeks during cooler times and once per week during the hottest months. But you water deeply, soaking the soil to a depth of 6 inches.
For St. Augustine grass, it's advisable to let the grass tell you when it needs watering, as it really hates being too wet. Instead of having a firm schedule, pay attention to your grass.
When it loses its vibrancy and starts to turn a dull bluish color, the blades start to curl, and your footprints stay on the grass long after you've moved on, you know it's time to break out the hose or turn on the sprinklers.
How to Mow St. Augustine Grass
Keep St. Augustine grass to a height of 2 to 3 inches. Try not to let the grass get much longer or when you mow the lawn, you risk mowing beyond the grass blade into the stem, which causes significant damage to your lawn.
Don't be tempted to scalp the lawn by mowing it super short, as again, you'll damage the stems and roots. Plus, you'll stop the blades from photosynthesizing properly and weaken the plants, making your lawn susceptible to pests and infection.
When mowing St. Augustine grass, never cut more than ⅓ of the length of the lawn in one mow session, as you'll shock the plants and can kill off patches of the lawn as you damage stems and chop off the nutrient supply. You're better off mowing less height more frequently to trim the grass but keep it healthy.
Chinch bugs are the main foe of St. Augustine grass. When these tiny black insects suck on the blades of grass, they also inject a toxin that prevents them from absorbing water properly, eventually killing it. If they are a problem in your area, consider planting a resistant cultivar, such as Seville.
The best measures against chinch bugs are preventative: Be sure to keep your lawn watered, especially during periods of hot, dry weather. Dethatching your lawn in the winter is also helpful to combat an infestation, as this will help uproot and destroy eggs, nymphs, and hibernation sites. In severe cases, try an insecticide with bifenthrin, and carefully apply it according to the manufacturer’s instructions.
The aggressive growth habits of St. Augustine grass help it naturally block out weeds. However, it can occasionally come up against broadleaf weeds such as clover, chickweed, and dollar weed. The best way to deal with weeds is to manually pull them up by the root, but a spot treatment with herbicides or vinegar will kill them, too.
St. Augustine grass is commonly afflicted with Downy Mildew Disease, which causes yellow to light green spots with a fluffy white growth on the leaf’s surface. Since this disease thrives in chronically moist conditions, the best thing to do is aerate your lawn and dethatch it to maintain optimal air circulation and soil drainage. If you spot diseased patches, dig them out before they can spread.
St. Augustine Grass Yearly Schedule
To keep your St. Augustine grass happy, follow this annual maintenance schedule.
End of winter: Fertilize it as soon as it finishes coming out of its winter dormancy and reestablishes its green color.
Spring: Water it lightly and frequently to keep the soil moist.
Summer: In the summer, fertilize it every six to eight weeks until growth slows down in the fall.
St. Augustine Grass Maintenance Tips
Need extra help maintaining your St. Augustine-filled lawn? Follow these tips and tricks.
Don’t overwater. Too much water weakens the grass.
Be prepared to see stiff seed stalks that grow above the grass blades. Mow more often (while still keeping your grass length at least 2 inches high) if you don’t like how the seed stalks look.
Keep your mower blades sharp, or you’ll tear and damage your grass.
Consider hiring a local lawn care service to mow for you if you don’t have the time to do it consistently.
St. Augustine vs. Other Types of Grass
Here’s how St. Augustine compares to these popular warm-season grasses.
St. Augustine Grass vs. Bermuda Grass
Looking at Bermuda grass vs. St. Augustine grass, both are beautiful and popular grasses for Southern lawns. Bermuda grass is more drought-tolerant, while St. Augustine grass is more shade-tolerant. Bermuda grass is sturdier, so it’s the better option for high-traffic lawns.
St. Augustine Grass vs. Centipede Grass
When comparing St. Augustine grass vs. centipede grass, appearance is a major distinguishing factor. Centipede grass has a bright yellow-green color year-round, while St. Augustine grass’ emerald-to-bluish-green blades go dormant and lose their color in the winter. Centipede grass is lower maintenance but more susceptible to wear and tear. However, St. Augustine grass has better shade tolerance, so it’s the best option for shadier lawns.
St. Augustine Grass vs. Zoysia Grass
Zoysia grass has finer blades and a smoother, softer feel than St. Augustine grass. It’s not as shade-tolerant, but Zoysia grass is more drought-tolerant and stands up better to foot traffic.
Frequently Asked Questions
St. Augustine grass grows fast thanks to its dense mat-like structure and vigorous root system. If you've laid St. Augustine sod, it'll put down roots, get itself established, and start to spread in 14 days.
St. Augustine is a hardy grass that’s relatively easy to grow, but it requires regular lawn maintenance to stay healthy. It’s best to keep up with a regular fertilization schedule during the growing season, plus a yearly dethatching to help it properly absorb air and moisture. Watering is also important, so be sure to water it enough to keep the soil moist.
In many cases, it’s a good idea to water St. Augustine grass daily to keep the soil moist and the grass thriving. It’s drought-tolerant, but it’s always best to keep it watered. However, it’s also important not to overwater, so skip watering during wetter conditions and aerate your lawn to promote proper soil drainage.
The best hardiness zones for St. Augustine grass are USDA growing zones 8, 9, and 10. However, with a bit of extra attention, it'll also grow well in zones 7, 11, and 12.