By Bonnie L. Grant, Certified Urban Agriculturist
St. Augustine grass is a salt tolerant turf suited for subtropical, humid areas. This article provides information on growing and caring for this versatile grass in your lawn. Click here to learn more.
Factsheet | HGIC 1211 | Published: Jan 27, 2016 | Print
St. Augustinegrass (Stenotaphrum secundatum) grows best during the warm (80 to 95 °F) months of spring, summer and early fall. It grows vigorously during this time and becomes brown and dormant in winter. It is considered to be native to the coastal regions of the Gulf of Mexico and the coastal regions of the Mediterranean.
This grass has large flat stems and broad coarse leaves somewhat similar to centipedegrass. It has an attractive blue-green color and forms a deep, fairly dense turf. It spreads by long, above-ground runners or stolons. While it is aggressive, it is easily controlled around borders. It is planted by vegetative means, including sod, sprigs or plugs.
St. Augustinegrass is the most shade-tolerant warm-season grass, although it still needs 4 to 6 hours of sun to thrive. It is very susceptible to winter injury, especially if planted farther west than Columbia. There has also been documented winter injury along the northern coastal regions of South Carolina. Despite the chance for winter injury, it is well-suited for the coastal plain and has a fair tolerance to salt.
St. Augustinegrass is considered a high maintenance turfgrass. On sandy soils, you can expect to fertilize monthly during the growing season with fertilizer applications every 6 weeks on clay soils. See HGIC 1201, Fertilizing Lawns for specific fertilizer recommendations. Supplemental iron applications along with micronutrient supplements may be needed on soils with a high or alkaline pH.
St. Augustinegrass should be mowed at the recommended mowing heights or at a height where scalping is not an issue. Mowing St. Augustinegrass too short will stress the turf and cause it too thin. Mowing too high will result in a thatch problem and disease issues as the lower grass canopy will tend to stay wet. A rotary mower can be used but must be sharpened monthly to maintain a healthy turf. If the tips of the grass blade look torn after mowing as opposed to cut, it is time to sharpen your mower blade.
St. Augustinegrass should be watered as other turfgrasses. When irrigating, apply ¾ to 1 inch of water. Allow the turf to thoroughly dry before irrigating again. Localized dry spots can be hand watered as needed. Automatic irrigation systems should be set to manual and run when needed as long as someone is there to monitor the turf.
Perhaps the greatest disadvantage of this grass is its sensitivity to an insect, the chinch bug. Chinch bugs can cause extensive damage to St. Augustinegrass if not controlled early. Most of the improved cultivars of St. Augustinegrass are also susceptible to several turf diseases including large patch and gray leaf spot. Both insect and disease problems can be successfully managed by implementing recommended cultural practices and pest monitoring. For more information on disease control, please see HGIC 2150, Brown Patch & Large Patch Diseases of Lawns and HGIC 2151, Gray Leaf Spot on St. Agustinegrass.
Weed control can also be a challenge when growing St. Augustinegrass. The control of grassy weeds using a postemergent herbicide can be difficult as the choice of a labeled herbicide is limited. This leads grassy weed control to be largely limited to a preemergent herbicide program. Broadleaf weed control is a bit easier using one of the broadleaf weed control products. The limitations to these herbicides are the heat of summer (>90 ºF), and the sensitivity during spring green up time. Please see HGIC 2310, Managing Weeds in Warm-Season Lawns, as well as specific weed control fact sheets.
There are several cultivars of St. Augustinegrass available in South Carolina. The differences between the various improved cultivars are their ability to resist pest, tolerance to environmental stresses, management inputs and their growth habits.
The cultivars below are grouped according to their mowing height. As a general rule, standard cultivars should be mowed to a height of 3 to 4 inches with the dwarf cultivars being mowed to a height of around 2½ inches. Use the higher mowing height under shade and stress conditions and the lower height in full sun under ideal growing conditions.
Anyone know what this is? It keeps popping up growing on / around the blades of grass in my St. Augustine. When I kick it or spray it with a hose it bursts and what appears to be dark dust flys out. Grass blades look almost charred after it's gone.
Thank you for the additional information. Yep, you have a fungus for sure, not a mushroom. With fungi, you will need to use a fungicide. Avoid disturbing the fungus pod so that you will not spread any more of the fungus spores. I would recommend carefully removing as many of the pods as you can locate. Careful place the pods in a zip lock back and dispose the bag in your regular trash receptacle if you have a separated trash pickup with your city. Since product availability will be different depending on your location, check with your local Home Depot Garden Specialist for recommendations. To be effective, you will want to use liquid based fungicide.
To help avoid cross contamination as you are removing the fungus pods, wipe your cutting tool after each cut with a diluted bleach mixture, about 3 tbls per 32 oz. bottle. You will want to cover your shoes with a disposable shoe covering available in the paint department. This will also help to prevent spreading the spores to your front yard.
Planting St Augustine Grass Plugs is simple. Just follow these steps:
The best time to plant St. Augustine plugs is in the late spring or early summer. By this time in the southeast, temperatures are well above 80℉. Even if you get a late start into the summer, it is likely still safe to plant plugs. Planting in the late summer should be mindful of the estimated first winter frost. St. Augustine plugs needs at least 90 days before the first frost.
The first step is to examine and calculate the area of the space needing plugs. The amount of space covered by a tray of St. Augustine plugs can vary by plant spacing.
|6" x 6" Spacing||24 Square Feet|
|12" x 12" Spacing||32 Square Feet|
|15" x 15" Spacing||40 Square Feet|
|18" x 18" Spacing||56 Square Feet|
Always take time to properly prepare the soil prior to installing your grass plugs. The time taken ensures your grass plugs will not die off. It also allows your grass to spread as quickly as possible. To prepare the soil, do the following:
After you have removed the vegetation, plan out the desired planting grid pattern. It is easier to flag where you will place St. Augustine plugs before digging. Space plugs in a diamond pattern to reach the square footage coverage in the table above.
Next, dig the holes for the plugs. Planting will be easier and have better success if the hole is larger than the plug. Use a garden trowell to dig holes. We recommend saving time and your back, by using the Corona LG3720 SodPLUGGER. Plug hole depth will vary based on the amount of root system on the St. Augustine plugs. Typically, holes will be between 2”-4” deep.
After the holes have been dug, thoroughly water the area. Water the soil until it is saturated. Be sure not to water the area to the point where water is standing or pooling in the holes.
Our specialists recommend adding a small amount starter fertilizer to the holes. By doing this you are putting fertilizer in direct contact with the developing roots. Ferti-lome New Lawn Starter Fertilizer will give your plugs a kickstart and make them grow faster!
Now you are ready to plant the St. Augustine sod plugs! Place the plugs into the predug holes at ground level. If the holes are too deep, add a small amount of soil to level the plug. Ensure that you cover the roots, but not the crown of the plug.
Planting the plugs too deep could cause the crowns to rot. Planting too deep also encourages diseases or insects. Fill in any space around the plugs with soil to secure.
Lastly, water the plugs again. Be sure to thoroughly wet without causing water to pool. It is important to continue to water the newly planted St. Augustine plugs for the next two weeks. After two weeks, continue watering the area with 1” of water per week.
Within two weeks, your St. Augustine plugs should be well rooted and on their way to spreading. Once the plugs have begun to spread, the area can be mowed as needed. Be sure not to cut the newly plugged area shorter than 2”.
St. Augustine grass plugs are a great way to fill in bare and dead spots. With a little care and patience, plugs will easily renovate your yard. Not only will it be the envy of the neighbors, you can do it 10x less than using sod.
Article photo courtesy of Sod Solutions.
Root rot, brown patch, and a host of funguses are the most common diseases to strike a St Augustine lawn. Seeing diseased or brown spots appear on your lawn can be disturbing, but like people, lawns get sick from time to time. Proper fungicides and a little extra TLC can get your yard back on track.
St Augustine requires at least one inch of water per week at a minimum. However, m, more water may be needed during hotter months.
If you are applying more water to your lawn than the minimum and begin to see brown spots, you may be watering too much. As a matter of fact, excess water to St Augustine will often do more harm than good.
Overly moist soil plays a host to all types of mold and fungi that can damage your lawn. Dry out your ground and see if the fungus issue resolves with the moisture being removed.
Overfertilization can scorch and burn grass blades and leave your lawn with brown or dead spots. Also, overfertilization can make your property more vulnerable to fungal or insect attack.
A strained yard is not able to combat natural threats in the same way as healthy grass. Always follow a proper fertilization plan for your St Augustine lawn that has been customized to your climate.