There are many different turfgrass varieties to choose from when it comes to installing sod in a new home lawn. A lot of homeowners aren’t sure where to even start with this process. Learning about the different types of turfgrass varieties available is a great idea before making a commitment to a type of grass. It’s also important to note that there are a few big key differences between warm season and cool season varieties. This particular Sod University blog focuses on the generic differences between zoysia and St. Augustine grasses. There are many types of St. Augustine and zoysia grass available to the homeowner, so a lot of these characteristics may vary depending on the cultivar of St. Augustine and zoysia selected for sod installation.
This is one of the most difficult features to compare because different varieties of zoysia have different colors. The same can be said with St. Augustine. For example, EMPIRE® Zoysia has a dark green color whereas Palisades Zoysia has a much lighter green color. On the other hand, CitraBlue® St. Augustine is known for its deep blue-green color whereas Floratam St. Augustine has a medium green color with red stolons. Take a look at the list and images below to get a visual representation of what these grasses look like.
EMPIRE Zoysia: Dark Green
Innovation Zoysia: Dark Green
Geo Zoysia: Deep Green
Zeon Zoysia: Deep Green
Zorro Zoysia: Deep Green
El Toro Zoysia: Dark Green
Palisades Zoysia: Light Green
Meyer Zoysia: Emerald Green
Pictured above from left to right: EMPIRE, Innovation, Geo Zoysia and Zeon.
Pictured above from left to right: Zorro, El Toro, Palisades and Meyer Zoysia.
St. Augustine Colors:
Palmetto St. Augustine: Emerald Green
CitraBlue St. Augustine: Deep Blue-Green
Floratam St. Augustine: Medium Green
Raleigh St. Augustine: Medium Green
Pictured above from left to right: Palmetto, CitraBlue, Floratam and Raleigh St. Augustine.
Blade Width and Texture
Zoysias and St. Augustines don’t only differ in color—they also differ in blade widths. St. Augustines have a much thicker blade than zoysia grasses. Zoysias have a thick, soft carpet with a stronger, medium-thick grass blade that produces a soft feel. Wider-bladed zoysias, like EMPIRE, usually have a blade width of 5–7 mm, whereas finer-bladed zoysias, like InnovationTM Zoysia and Geo® Zoysia, have a blade width around 2 mm. Overall, zoysias are typically fine turfgrasses with a smooth feel. St. Augustine blade widths vary as well. Most St. Augustines have a blade width of 8–9 mm, but superior St. Augustine varieties like CitraBlue have a blade width of 5–7 mm. St. Augustine grass is coarse-textured with a very thick grass blade that rounds at the top and becomes more compacted towards the soil. Overall, St. Augustine blades are flat and broad and can form a dense layer of grass with a coarse feel.
Pictured above from left to right: Innovation Zoysia and CitraBlue St. Augustine.
Both zoysia and St. Augustine grasses are pretty shade tolerant compared to other turfgrass varieties. It should be known that St. Augustines are the most shade tolerant warm season turfgrass varieties available. CitraBlue and Palmetto® St. Augustine are the best grasses for shade. When it comes to zoysia varieties, zoysia is still pretty shade tolerant for a warm season grass, but their shade tolerance ranks second to that of St. Augustine’s. Finer-bladed zoysias, such as Innovation and Geo Zoysia, are more shade tolerant that the thicker-bladed zoysias like EMPIRE. To learn more, read Growing Grass in Shaded Landscapes.
Mowing Heights and Growth Habits
Each variety of grass requires different mowing heights to perform and looks its best. Zoysia grasses are usually mowed at a height of .5–2 inches whereas St. Augustines are generally mowed at a height of 2–4 inches. Specific zoysia and St. Augustine varieties may differ, but they generally fall pretty close to their generic mowing heights. For example, Innovation should be mowed at a height of 1–2 inches whereas CitraBlue performs best at a mowing height of 2.5–3.5 inches. There are also outliers like Palmetto, a semi-dwarf St. Augustine, which should be mowed at a height of 1.5–2.5 inches. Mowing heights matter because they usually dictate how frequently homeowners will need to mow. Different varieties grow at different speeds, so this isn’t always the case.
All zoysias spread via rhizomes and stolons. A rhizome runs underground horizontally—often just underneath the surface of the soil. Rhizomes strike new roots downward into the soil and also shoot stems upwards. A stolon is an above-the-ground stem that creeps along the surface of the soil and subsequently grows a clone of the original plant on the end of it. St. Augustines only spread through the above-the-ground runners, stolons. They are usually better than zoysias at choking out weeds for this reason. Since zoysias grow with both methods, they usually rank higher in wear tolerance, injury recovery and drought tolerance. They also recover better from dethatching and lower mowing heights. To learn more, check out our Lawn Mowing Guide.
Pictured above: A St. Augustine stolon growing across the surface of the soil above ground.
Zoysias typically rank higher in wear tolerance and injury recovery than St. Augustines. The wider-bladed zoysias are considered “very good” with wear tolerance and injury recovery. The finer-bladed zoysias don’t tolerate wear as well and aren’t as fast at recovering compared to the wider-bladed zoysias. St. Augustines are considered “good” with wear tolerance and injury recovery, although the superior variety, CitraBlue, has a better wear tolerance than most other St. Augustine varieties. This is why zoysia grasses can be found in golf courses instead of St. Augustines—zoysias are generally more durable.
Drought Tolerance vs. Drought Resistance
Drought tolerance is the ability to survive a drought. In comparison to drought tolerance, drought resistance is the ability to look good during drought. Although both zoysia grasses and St. Augustines require about one inch of water per week including rainfall, zoysia grass varieties have the ability to survive during a period of drought. During periods of drought, zoysias go off-color with their natural dormancy mechanism. They will then return to color shortly after resuming a regular watering schedule. St. Augustines, in comparison, will hold color better than zoysias and have a higher drought resistance, but when they start to turn brown from a lack of water, they’re dying—not preserving themselves with dormancy. CitraBlue St. Augustine is again an outlier in this particular category because CitraBlue’s drought tolerance is better than most St. Augustines.
Soil Preferences and Salt Tolerance
Zoysia and St. Augustine can perform well in a wide range of soil types and climates, but there are soil types that they perform better in than others. There are three main types of soil: sandy, clay and loamy soil. Zoysia will perform well in all three of these soils whereas St. Augustine performs best in loamy and sandy soils. St. Augustine also tends to have a higher salt tolerance than zoysias, so you will typically see more St. Augustines along the coasts or around areas high in salt content. Zoysias, in comparison, only have a moderate salt tolerance. For more information on the differing soil types, be sure to take a look at our Soil Management for Lawns and Gardens blog.
Fertility and pH
No matter which type of turfgrass variety you choose for installation, every one of them is going to need some form of nutrition. They are living products, so they require nourishment just as we do. This is more than just water and sunlight. Both St. Augustine and zoysia require a certain amount of macro and micronutrients including nitrogen, phosphorus, potassium, iron, manganese and sulfur.
Zoysias tend to perform best in soils with a pH between 5.8–7.0. They are also more tolerant than St. Augustines of soils with poor drainage. St. Augustines perform well in soils with a wider pH range that’s between 5.0–8.5, but St. Augustines need soils with good drainage to thrive. Lastly, be sure to check out the Lawnifi® fertilizer program—the perfect fertilizer program for both zoysia and St. Augustine. While the nutritional needs for both grasses slightly vary, Lawnifi meets their main requirements. Be sure to take a look at a few related Sod University blogs on Collecting and Submitting a Soil Analysis and Why Use Lawnifi Fertilizer?.
Zoysias and St. Augustines can be plagued by different insects, bugs and grubs including mole crickets, billbugs, armyworms, white grub worms, sod webworms, ants, grass spiders or spittlebugs. You can learn more about some of the most common of these in our Insect Identification blog. Zoysia grasses, in particular, are usually more prone to insects like billbugs. There are some superior varieties, like Innovation Zoysia, that are immune to the bluegrass billbug, however. EMPIRE is another zoysia grass that demonstrates immunity to another common pest found in St. Augustines—the chinch bug. Homeowners who’ve had problems with these pests in the past may like EMPIRE or Innovation more for this reason. St. Augustines, however, are more prone to pests like chinch bugs, white grub worms, sod webworms or fall armyworms that love to feed on the grass blades and roots. For either type of grass, it is a good idea to apply a systemic insecticide that is labeled to treat such insects preventatively before problems become out of hand. Take a look at some of our most popular insecticides below. Be sure to read each label thoroughly before application.
Similarly to insects, both zoysia and St. Augustines, along with every other grass type, are prone to more diseases or fungus outbreaks than others. Knowing which types of diseases these two grasses are more susceptible to will really help in preventing and treating any future outbreaks that may occur. Although both grasses can encounter many different fungus outbreaks, the ones zoysias most frequently experience are brown spot, rust and leaf spot. St. Augustines frequently experience brown patch and grey leaf spot. Take a look at some of our top recommended products for these lawn diseases. Each product is labeled with application instructions to treat certain turfgrass diseases. Be sure to read each label thoroughly before application. For more information, read our Lawn Disease Control blog and our Identifying Common Lawn Diseases blog.