St. Augustine grass (Stenotaphrum secundatum) is sometimes called "buffalo grass," although a different plant (Bouteloua dactyloides) is what people usually mean when they refer to the latter. St. Augustine grass is a spreading, warm-season grass for lawns, especially in warm climates.
It is a true grass as a member of the Poaceae family. St. Augustine grass identification is based on its bluish-green leaf color with wide, flat blades and low, creeping habit that allows it to form dense mats. It spreads via stolons. St. Augustine grass is a salt-tolerant making it an ideal choice for people who live along the coast.
|Common Names||St. Augustine grass, buffalo grass, carpet grass, couchgrass, quickgrass, wiregrass, mission grass, pimento grass, Charleston grass|
|Botanical Name||Stenotaphrum secundatum|
|Plant Type||Herbaceous, perennial grass|
|Mature Size||6 to 12 in. tall|
|Sun Exposure||Full sun to partial shade|
|Soil pH||6 to 7.5|
|Hardiness Zones||7 to 12, USDA|
|Native Area||The Caribbean, South America, southeastern U.S. in the New World; Africa and Asia in the Old World|
St. Augustine Grass vs. Bermuda Grass
St. Augustine grass and Bermuda grass perform best in the southern regions, or warmer parts of the U.S. St. Augustine grass blades are coarser and broader, about 1/3 of an inch in width. In contrast, Bermuda grass is less than 1/10 inch wide and more soft and delicate in texture.
- Shade tolerance: St. Augustine grass and Bermuda grass are warm-season grasses that love full sun, but an advantage of St. Augustine grass is that it can also grow in shady spots, while Bermuda grass can't.
- Cold tolerance: Bermuda grass is slightly more cold-tolerant than St. Augustine grass, able to withstand an occasional cold snap better. It's preferred for southern states like Tennessee, North Carolina, Central California, Oklahoma, or Arkansas, which experience colder temperatures.
- Drought resistance: Bermuda grass needs only half the water as St. Augustine grass, which, by comparison, is a water hog. Bermuda grass can outlast periods of drought better than St. Augustine grass.
- Fertilizer needs: St. Augustine grass needs almost twice as much fertilizer (heavier in nitrogen) than Bermuda grass. Bermuda grass requires about 1 to 4 pounds per 1,000 square feet per year, vs. St. Augustine grass, which needs 3 to 6 pounds per 1,000 square feet annually.
- Propagation: Bermuda grass can be grown by seed, while St. Augustine grass only grows from transplanted sod or plugs.
- Weed resistance: Sodded St. Augustine instantly chokes out any weeds. Also, since its primary spread method is by stolons or runners, it can speedily overtake a Bermuda grass lawn primarily grown from seed.
- Salt resistance: St. Augustine is a better choice for coastal areas. It can tolerate salty conditions better than Bermuda grass and is a popular choice from the coasts of Florida to Texas.
- Cost difference: Sodding St. Augustine grass is significantly more expensive than seeding, so Bermuda grass is a more cost-friendly option since it can be seeded. Also, Bermuda grass needs less fertilizer and watering in a year, keeping those extra costs down.
St. Augustine Grass Care
One of the great virtues of St. Augustine grass is that you don't have to mow it much, a fact that you will especially appreciate if you crave low maintenance. However, to achieve a lush lawn of St. Augustine grass, there is some work involved. You will have to keep up with the required irrigation and fertilization.
As a warm-season turfgrass, plant St. Augustine grass in spring and summer in full sun with at least 90 days to establish before first frost.
St. Augustine grass prefers full sun but can also tolerate some shade. But, for best results, grow St. Augustine grass in full sun. Of the warm-season grasses, St. Augustine grass is the most shade-tolerant.
Provide St. Augustine grass with good drainage. A good garden loam works well.
For best results, keep its soil evenly moist. St. Augustine grass is tolerant of a wide variety of soils and is moderately drought-tolerant once established, but it will perform best when you avoid either moisture extreme: too little or too much.
Temperature and Humidity
St. Augustine grass handles heat and humidity well, which is why it is popular in regions such as the American Southeast.
St. Augustine grass performs best if fertilized regularly, on a schedule. Fertilize it initially in spring after it has finished greening up. During the summer, maintain a fertilizing schedule such that you feed it every 6 to 8 weeks. Any all-purpose grass fertilizer will be sufficient, but be careful to follow the application instructions on the package.
Types of St. Augustine Grass
There are a number of different types of St. Augustine grass. Examples include:
- Floratine: offers narrower blades, for a finer texture
- Floratam: a chinch bug resistant selection, but not as cold-tolerant
- Seville: This selection offers both a finer texture and resistance to chinch bugs, but it also lacks cold tolerance.
Propagating St. Augustine Grass
St. Augustine grass has traditionally been propagated via sod (plugs), and it is in this form that turf farms or their retailers sell it to homeowners and landscapers. Since St. Augustine grass spreads so vigorously via its creeping stolons, it is easy to establish it from sod. In zones 7 to 12, you can start a lawn of St. Augustine grass any time during the growing season. Space the pieces of sod 1 to 2 feet apart and water faithfully. The grass grows fast enough to bridge the gaps during the first year.
How to Grow St. Augustine Grass From Seed
Most St. Augustine seed is naturally sterile. St. Augustine grasses do not produce enough viable seeds for commercialization. It is rare to grow St. Augustine grass from seed. But, if you are lucky enough to find the seed and want to try your hand at it, sow it in late spring to early summer. Sow 1/3 to 1/2 of a pound of the seed per 1,000 square feet. Pay special attention to keeping the ground evenly moist until you see that the grass has not only sprouted, but also begun to spread.
St. Augustine grass will only stay green all year if the soil temperature remains 60 F or warmer. So, unless you live in the subtropical regions of Florida and California, St. Augustine grass will turn brown in winter. As long as you are in at least zone 7, don't worry: It's not dead, just dormant. It will become green again when warm weather returns.
Disadvantages of St. Augustine Grass
- Not as hardy in cold weather as other grasses
- Not drought tolerant
- Does not stay green in winter
- Needs a heavier fertilizer regimen
- Does not spread by seed; requires sodding or plugs
- Can handle regular foot traffic but not heavy, repeated traffic
Common Pests & Diseases
St. Augustine grass is prone to attacks from insects and diseases.
St. Augustine grass is susceptible to infestations of chinch bugs. What makes these pests so deadly is that they do not merely eat your grass: They also inject a toxin into it. This toxin renders your grass unable to take up water properly, and the grass dies.
Prevention is the best way to control chinch bugs. Happily, the preventive measures required dovetail with the lawn care tasks you should be performing regularly (even if you don't fear a chinch bug infestation). Since you must eliminate dryness and thatch to ward off chinch bugs, simply make sure you:
- Water as needed, especially during hot, dry spells.
- Dethatch your lawn whenever you detect substantial thatch build-up.
St. Augustine grass can be attacked by downy mildew disease. You can prevent downy mildew through good garden hygiene:
- Poor air circulation promotes diseases such as downy mildew. They thrive in wet, humid environments. Aerate and dethatch your lawn as needed to foster better air circulation.
- Water early in the day so that the grass blades have time to dry before nightfall.
- Dig out and dispose of any diseased patches of sod as soon as you find them.
How fast does St. Augustine grass grow?
St. Augustine grass grows more quickly than many other lawn grasses.
Will St. Augustine grass take over weeds?
St. Augustine grass is an aggressive grower and can compete with weeds.
How long does a St. Augustine grass lawn last?
A St. Augustine grass lawn can live for three to five years with regular maintenance, including watering, mowing, fertilizer, and aeration. This warm-season grass goes dormant in winter.
Can I put St. Augustine grass over my existing grass?
It's best if you put St. Augustine grass directly on the soil. The grass needs soil to establish its roots.