Everything About Zoysia Grass
Zoysia grass can be an ideal lawn grass option for those who live in a hot climate, are looking for a dense lawn, and don’t have a lot of time for lawn maintenance.
Published: October 21, 2022.
What is Zoysia Grass?
Zoysia grass is a perennial warm-season grass that loves heat, and is high traffic- and drought-tolerant. It’s native to East Asia and was named after Karl von Zois, an 18th-century Slovenian botanist.
Its different species were brought to the United States over a period of several decades. For example, Zoysia japonica was brought to the US from the Manchurian province of China in 1895, whereas Zoysia matrella came to the US in 1911 from the Philippines (& hence is also known as Manila grass).
Zoysia is grayish-green in color and has a fine soft texture. Just above the junction of its stalk and leaf, there are tiny hair-like structures. The grass grows upright and due to its soft feel, it’s pleasant to walk upon barefoot.
Zoysia is at its best in full sun. However, it can withstand partial shade. But the grower has to expect thinner lawns in the shaded areas. It also cannot withstand wet soil and hence those with heavy clay should consider another grass variety for their lawn.
Zoysia doesn’t want a lot of water to remain green throughout the summer and does well with less irrigation. Also, since it’s slow-growing in height, it doesn’t even need a lot of mowing. However, it tends to have a lot of thatch and so, needs to be aerated more frequently than other grasses.
Zoysia grass quickly spreads out, often competing with weeds and other grasses. It’s usually grown with sod rolls or plugs, rather than with seeds. Apart from home lawns, it’s a preferred choice for football and baseball fields, and golf courses. Being salt-tolerant and adaptive to sandy soil conditions, it’s also found on the coasts of the United States.
Zoysia grass is commonly used in the southern 2/3rd part of the United States since it does well in the heat and also tolerates shade in this region. It performs the best when daytime temperatures range between 83°F and 96°F. But unlike other warm-season grasses, like St. Augustine, centipede, bahia grass, and Bermuda, it can survive in cooler conditions.
However, it goes dormant and turns brown when temperatures drop below 55°F. But this doesn’t mean that it’s dead. When the temperature rises again, it regains its color.
Zoysia grass has strong, medium-thick grass blades that are soft to touch. It spreads both by stolons (above-ground stems) and rhizomes (underground stems) and hence has excellent tolerance against heat, drought, and other environmental stressors. Since its root system is deep, it’s capable to survive environmental stressors.
It adapts to a wide range of soils including clay, sandy soils, and loamy soils with acidic and alkaline pH ratings. This grass goes dormant quite quickly with the year’s first frost. However, it’s also one of the first to turn green again with the arrival of spring.
Zoysia grass grows best in the USDA plant hardiness zones 6 to 11. The best parts it grows well in are the southern, southwestern, and transition zones.
Due to its hardiness, its growing zone can be stretched to encompass southern Kansas, southern Maryland, Central Arkansas, Missouri, and large parts of Kentucky as well as Tennessee.
Zoysia Grass Varieties
There are several varieties of zoysia with different qualities and characteristics. Growers can choose a variety that suits the conditions in which they’re living.
Zoysia matrella: Originating in Southeast Asia and also known as Manila grass, this variety has a fine leaf texture. It performs well in hot and humid climates. Its varieties are Zeon and Diamond.
Zoysia japonica: Native to Southeast Asia and also known as Japanese lawn grass or Korean lawn grass, this variety has the highest tolerance against cold and drought and can adjust well to changes in sunlight, temperature, and moisture. It’s also resistant to insects and weeds. It’s light green in color and has a medium texture. Its varieties include Meyer, Zenith zoysia, and El Toro.
Zoysia tenuifolia: Also known as Korean velvet grass, Z. tenuifolia has a fine soft texture and typically grows in mounds or lumps instead of a smooth lawn. This habit makes it less popular as lawn grass as it’s more suitable as a small ornamental plant. The most common variety is ‘Emerald’ which is perfect for those who are looking for a soft lawn with thin blades. Emerald is lower growing too and hence needs to be mowed only once or twice per month.
Zoysia macrantha: This variety is native to Australia and performs well in areas that are excessively sunny. Its color is light green and its texture is coarse and prickly.
When to Plant?
The best time to plant zoysia grass is mid to late spring (when there is no chance of frost left) to early summer. One can even plant zoysia in early fall, but they should plant it at least 60 days before the first expected fall frost.
Any time beyond that the planted seed may not survive the winter since it won’t get sufficient time to establish in the soil before the arrival of winter weather.
How to Grow Zoysia Grass
Zoysia grass can be planted from seeds, sods, or plugs. However, growing from sod is a more popular method than growing from seeds.
A zoysia lawn grown from seeds in a warm region where it receives a lot of sunlight might take a year to fully establish, while a lawn grown from plugs in the same conditions might take two or even 3 years to establish fully.
However, during this period, the grower should combat weeds which may prevent growth. Some homeowners may be irritated due to such a long waiting period. Growing from sod shortens this period from years to merely some weeks. The disadvantage of sod is that it’s often quite expensive.
Note: New innovative zoysia seed varieties take less time to grow and thus make a good option for growing zoysia grass lawn. These varieties are more economical and outperform the sod or vegetative varieties in several ways. Zenith is such a variety and it’s the newest seeded version of zoysia.
Choosing the Planting Site
Zoysia grows best in full sun and will root quickly if it gets at least 6 hours of direct sunlight per day.
Although once established, zoysia can tolerate moderate shade and will grow (slowly though) in lightly shaded areas beneath shrubs or trees, a new zoysia lawn cannot be started from seed if any part of the planting area receives even partial shade and the gardener should compulsorily plant sod in that area.
Shade affects so severely that even an established zoysia lawn in need of repair in existing grass will often stop growing from seed in shade.
Before planting seeds, sod, or plugs, the grower should perform certain tasks. They should start them in late winter or early spring so they can plant zoysia in late spring or early summer.
Measuring the Yard
Before planting, the grower should measure their garden so they can determine how much seed, sod, plugs, topsoil, and fertilizer they’ll need without falling short or buying extra.
Testing the Soil
The grower should test their soil to check if the soil has the right balance of nutrients. A soil test is inexpensive and one’s local extension office can provide it. The grower should take at least 10 samples of the soil from different spots to do the test.
If they have large lawns in separate zones e.g. front yard and backyard, they should test them separately. A soil test also lets the gardener know if the soil has moderate levels of iron, nitrogen, potassium, and phosphorus or not.
When the grower receives the soil test results, they may have to adjust the pH of the soil. Zoysia likes a neutral pH of around 6.5 but can withstand anything between 5.8 and 7.0. If the gardener’s soil pH is higher than this, they have to add sulfur to lower it and if it’s less than this, they have to add lime to increase it.
Preparing the Soil
Once the soil pH is balanced for successful growth, the grower should prepare the soil. This is because, unlike cool-season grasses that can grow next to each other without any problem, warm-season grasses like zoysia are to be planted on their own for a successful lawn. Therefore unless the planting area has already a zoysia lawn that just needs a greater density, it’s best to choose bare soil to start a zoysia lawn.
For this, one should kill any other grass or weeds growing there with a non-selective herbicide such as glyphosate. This should be done in the weeds’ active growing period in the spring. The weeds and grasses killed in this way should be removed with a mower’s lowest setting.
If growers are growing zoysia from seed, they should then level the ground. They should break large lumps of soil with a hard rake, and also remove debris like rocks and sticks. Then they should form a fine, loose top layer for the seedbed with a soft rake.
In case of growing from seed, the grower should spread seeds in the prepared seedbed with a broadcast spreader. A broadcast spreader is the right tool to distribute seeds evenly.
Excessive seeds can result in overcrowding and a low sprouting rate. On the other hand, a low amount of seed can lead to a thin-looking lawn. After spreading seeds, they should press them in the soil with a lawn roller. Planted seed should be topped with peat moss. If the ground is sloping they should use mulch containing a tackifier.
In the case of plugs, the grower should use a plugger in a diagonal grid pattern with a distance of either 6 or 12 inches. The more plugs, the higher will be the cost; however, it’ll also result in a quicker establishment.
In the case of sod, the grower should roll out each rectangular sod of zoysia. They should place the rectangles in a brick-like pattern with the edges of each of them stuck tightly against the others.
After preparing the site, the grower should amend the soil surface with one inch of organic fertilizer or compost when they are about to grow the lawn from seed or plugs. But in the case of sod, there is no need to apply fertilizers as sod is heavily applied with fertilizers at the sod farm.
Then after 30 days of seeding, plugging, or laying sod, growers should apply fertilizers. If they want to apply sea kelp and humic acid, they can also do that during this period.
Till their germination, zoysia seed should be kept consistently moist. This can be achieved with a hygroscopic product.
In the case of sod, right after laying the sod, the grower should water the lawn to ensure soil contact with the grass. It typically takes from 2 to 3 weeks for the sod to root firmly. During this period, the grower should take utmost care of the lawn. They should provide a one-quarter inch of water to it twice daily.
Plugs should be also regularly watered for the first three weeks.
How to Take Care of Zoysia Grass
While the grass is rooting, one should strictly avoid walking on it or crushing it.
Zoysia grass needs only around 1 inch of water weekly. However, the watering frequencies and timing will change every season.
The grass will turn brown during drought conditions but will regain the color once the gardener waters it again or when it receives rainfall. Watering the lawn 2-3 times a week depending on temperatures and soil conditions will help it recuperate.
In areas with hot temperatures or sandier soils, more water may be required. If the grower lives in a warmer climate, it’s a good idea to water zoysia occasionally during the winter months. Excessive watering may cause diseases. While the grass is in active growth, the gardener should water to prevent drought stress, after the beginning stages of dormancy to keep dehydration away.
The gardener should provide Zoysia with 2 ½ to 4 pounds of nitrogen per thousand sq. feet per year. They should also provide it sufficient quantity of potassium, phosphorus, and a variety of micronutrients.
But they should first test the soil every year and apply fertilizers according to its results. Nitrogen application should be done from May through August.
The gardener is better off with mowing their zoysia grass lawn up to 1.5 to 2 inches of height during the growth period. After this, they can mow the lawn up to 2 to 2.5 inches during the fall.
Just like all other grasses, zoysia grass should not be mowed to remove more than 1/3rd of the grass blade at any one mowing round. It’s also good to mow it higher in areas that receive shade. Mowing also reduces the chances of thatch. Thatch may prevent the grass from absorbing water and nutrients.
In the fall, gardeners should mow less often. Keeping zoysia slightly tall will promote deeper root growth which in turn will help it endure colder temperatures and during winter dormancy.
As it is, zoysia grows slowly and so, hardly needs to be mowed more than once a week.
No matter how carefully the gardener handles a zoysia lawn, it will form a thick layer of thatch which should be removed. Liquid dethatching may help. However, it’s advisable to do a thorough mechanical dethatching with a verticutter or power rake once a year, possibly in late spring or early summer.
The commonest broadleaf weeds invading the zoysia grass lawn are clover, bluegrass (Poa annua), and dandelion. Broadleaf herbicides are the best to control them.
Pre-emergent herbicides prevent these weeds from arising. They should be applied in the spring and fall when temperatures start changing. Post-emergent herbicides will control weeds after they’ve emerged from the soil.
Gardeners in the south are tempted to make a mistake to overseed dormant zoysia with rye to enjoy a year-round green color.
However, though this technique may succeed with Bermuda grass, it doesn’t succeed on zoysia.
Firstly, a healthy zoysia lawn is typically too dense to allow much of the rye to grow, even if it’s dormant. Secondly, and more importantly, overseeding puts a lot of stress on zoysia which can cause problems during the next season.
Insects and Diseases
Zoysia is prone to white grub infestation. Inspection of soil under the grass during summer and fall is the most effective way to prevent the problem. The gardener should apply an insecticide if required; but if they use a granular variety, they should water the lawn instantly after the application to help soil absorption.
Chinch bugs can be a problem for zoysia grass lawns especially in the deep south. They can be killed using an insecticide.
Sometimes zoysia may be affected by a fungus which is seen as large patches.
In that case, the gardener should apply a fungicide at a level of prevention. Here too if they use a granular variety, they should water the grass right after using the fungicide to help soil absorption. The fungicide usage can be expensive; therefore they should consider mapping the areas of application. Here are some fungal diseases zoysia grass is prone to.
Large Patch: Large patch is the most common dangerous disease in zoysia. It’s most likely to appear when the soil is less than well-drained or in areas where the disease has occurred in the past. Applying the fungicide Azoxystrobin two times, once in mid-August and once in mid-September helps prevent it.
Brown Patch: This is one of the most prevalent diseases in zoysia grass and kills patches of the grass. It starts as small patches but quickly spreads in warm conditions. The disease can be identified by a brown ring that surrounds a green center.
Although spores of the fungus cannot be entirely removed, keeping the grass healthy can make it less susceptible to fungal growth. Gardeners should apply fertilizers only when needed and water in the morning after all the dew drops dry out. They can also use fungicides as mentioned above.
Rust: Rust in grasses usually is formed during cool, moist conditions. It appears on zoysia as an orange, powdery substance on the grass. Besides using correct fungicides, the gardener may need to save grass clippings after or during mowing and dispose them of properly to prevent further spread of the rust.
Leaf Spot: This disease occurs in zoysia during warm days and cool nights. It results from excessively dry conditions and a lack of proper fertilizers. It appears as small lesions on grass blades with particular patterns.
It’s often necessary to inspect the spotty areas of zoysia to determine the actual presence of the disease. Gardeners can apply fertilizers and water grass deeply at least once a week to help reduce the problem.
A gardener can establish a zoysia grass lawn and maintain it easily. Only a little effort can give them a lush green, a pleasant and soft lawn which they’ll be proud of.