For decades, beginning in the late 1970s and persisting well into the 2000s, if you were to open your Sunday newspaper you’d find tucked somewhere inside it a glossy ad touting the benefits of zoysia. The advertisers were selling plugs of zoysia grass; plant them in a bare yard, you were told, and be patient, it may take two years for the grass fill in, but once it does so you’ll have a lawn that is nothing short of miraculous. Zoysia was proclaimed to be trouble-free, weed-free, and worry-free. The sensational claims made about this grass were so numerous it was hard to fit all of them on the page: it only requires mowing once a month! It can grow in sun or shade! It tolerates any amount of traffic! It is cold hardy! Disease and insects can’t touch it!
Reading this, you likely assume that these claims amounted to so much nonsense, just another example of a too-good-to-be-true marketing swindle, like instant weight loss pills or lasers that prevent hair loss. Surprisingly, while many of these assertions were exaggerated, most of them are at least partially true. Zoysia certainly isn’t miraculous, but when grown in the right conditions, it will provide a beautiful, dense, durable and attractive lawn.
The Origins of Zoysia
Zoysia is a genus of grasses native to east Asia named after the 18th century Slovenian botanist Karl von Zois. Different species within this genus were introduced to the United States from various places over a span of several decades. Zoysia matrella was brought from the Philippines in 1911 and is for that reason is sometimes known as Manila grass. Similarly, zoysia tenuifolia came from the Mascarene Islands in the Indian Ocean and is often referred to as Mascarene grass. Both types are occasionally found in lawns in the southern United States, but these days are relatively rare. The most notable and prominent type is zoysia japonica. Despite being brought from the Manchurian province of China in 1895, it was for decades referred to as Japanese or Korean lawn grass. Regardless of any confusion over names, japonica is the most robust of the three and provides nearly all of the varieties that we see in home lawns today.
Is Zoysia Right For You?
The first and most important thing to say about zoysia is that it is a warm season grass, meaning it is at its best when daytime temperatures range from roughly 83-96°F. This is contrast with cool season grasses like Kentucky bluegrass, rye and fescue that do best when temperatures are closer to the 55-80°F range.
Unlike other warm season grasses such as bermuda, centipede, St. Augustine and bahiagrass, zoysia can survive in cooler conditions. This prompted many of the aforementioned newspaper advertisements to suggest it could be grown anywhere in the country. Believing this, many homeowners in northern areas that don’t typically have warm season grasses planted it. Even today, fifteen years after the decline of these ads, one still bumps into zoysia in unusually temperate places like upstate New York, Maine and Minnesota.
The fact that zoysia can survive in these places doesn’t, in and of itself, suggest it is a suitable grass type for cool climates. It is important to understand that zoysia will go dormant any time temperatures are consistently below 55°F, turning a nutty brown color and staying that way until warm weather returns. In many northern areas this dormancy could last for eight months or longer. If your goal is an attractive green lawn and you live in a northern area, I would suggest zoysia is not for you.
Where are good places to plant zoysia? The best places are going to be in the south and southwestern parts of the United States. However, because of its hardiness, zoysia’s zone could be stretched to include parts of southern Maryland, southern Kansas, Missouri, central Arkansas and large parts of both Tennessee and Kentucky.
Zoysia does best in full sun lawns. It can tolerate partial shade but one should expect the turf to be thinner in these areas. It also does not to do well in wet soils. Those with heavy clay would be best served with a different type of grass.
Identification and Characteristics
Zoysia has a grayish green color that is darker than centipede, but less blue-green than St. Augustine or bahiagrass and less true green than bermuda. It has tiny, delicate hairs that are found just above the junction between the leaf and the stalk. Zoysia grows in an upright manner and has finer blades than any of the warm season grasses. These fine blades combined with its relatively soft texture, give zoysia an appealing feel; it is one of the few warm season grasses that is enjoyable to walk on while barefoot.
Zoysia spreads via stolons, which crawl across the surface of the soil and root from nodes that form every inch or so, and rhizomes which function in a similar manner but beneath the soil. While it grows and spreads slowly, once established and healthy this stoloniferous and rhizomatous growth provide for a dense, thick stand of grass that does indeed choke out many weeds. I would never go as far as to say that zoysia is a “weed free” grass, but it certainly does a better job at naturally keeping weeds out than any other grass type.
Varieties of Zoysia
The are at least a dozen varieties of zoysia on the market today. Choosing the one most suitable to the conditions in the area it is to be planted is very important. Some notable types include:
- Meyer. Named after Dr. Frank Meyer, an American botanist and explorer who brought the seeds that eventually produced this grass from Korea in 1906, Meyer is the original commercial variety of zoysia and the one advertised in the newspapers for so many years. In truth, Meyer does do fairly well in some relatively northerly parts of the Transition Zone. It is slow to develop but has great color and density once it does. Meyer seed is occasionally marketed but because of variation in the grass that emerges from seed, it is best grown from sod or plugs.
- El Toro. Developed in California, this variety has the best shade tolerance of any zoysia. While sometimes sold in plugs, if it is going to be grown in the shade it is best when sodded.
- Emerald. A hybrid of japonica and tenuifolia, Emerald has a deep color and notably finer texture than Meyer. A well kept Emerald lawn can be downright striking in its beautiful appearance. It is best grown in the south or southwest as it struggles in cool temperatures. It is available only in plugs or sod.
- Empire. A relative newcomer, Empire is an excellent choice for home lawns, particularly for those homeowners with less lawncare experience. It is highly resistant to insects and disease and thus requires less maintenance and establishes more quickly than any other grass listed here. It is also only available as plugs or sod.
- Zenith. A decedent of Meyer, this is the only variety of zoysia currently available from seed. It does not grow quite as dense as Meyer does – a benefit to some as it is easier to mow – and does not have the color of Emerald or Empire. In my opinion, it is a small step down from the other varieties listed here, but it is certainly a quality grass.
How To Plant Zoysia
Zoysia can be established either from seed, plugs or sod. Each have their advantages and disadvantages. For seed and plugs, the biggest disadvantage is is zoysia’s slow, almost sluggish pace of growth. A seeded lawn grown in a warm place with lots of sunlight might be fully established in a year. A plugged lawn could take two or even three years to fill in. During this time weeds must be combatted or growth will be brought to a virtual standstill. Waiting so long for a desirable lawn can be agonizing for some homeowners. Sod shortens this waiting period from years to weeks. While it is unquestionably the best method of the three, it is often prohibitively expensive.
Because zoysia seed is more economical than sod and establishes faster than plugs it seems like an obvious choice. However, high demand coupled with poor yields on seed farms have led to a minimal supply of seed. What is around is quite expensive – roughly $35 to $40 per pound – and is limited to only one quality variety, Zenith.
If any parts the area to be planted receive even partial shade, sod will be mandatory in those areas. While established zoysia can live in the shade it will not grow from seed or spread from plugs in such spots. The impact of shade is so severe that even in an established zoysia lawn needing repair existing grass will often prevent growth from seed. Thus overseeding – a concept best left to cool season grasses – is nearly impossible. Plugs are the best option in situations like this.
No matter which option is selected, proper preparation of the site is essential. This process should begin in late winter or early spring, with a goal of planting or sodding in late spring or early summer.
STEP #1 – Get a soil test.
Regardless of whether it is zoysia or another type of grass being planted, before starting any sort of lawn renovation, getting a soil test is of critical importance. Use a soil probe to take at least ten samples in any area being tested. For large lawns separate zones – the backyard and front yard, for example – should be tested separately.
STEP #2 – Amend the pH, if necessary.
Once the soil test results are back the lawn may need to have its pH adjusted. Zoysia prefers a neutral pH of roughly 6.5 but will tolerate anything between 5.8 and 7.0. If the lawn’s soil is not in the range, you’ll want to add lime to raise your pH or sulphur to lower it.
STEP #3 – Clear the area.
Unlike cool season grasses which can grow side by side in the same lawn without issue, zoysia and all other warm season grasses are best grown on their own. Thus, unless the area to be planted is already a zoysia lawn simply in need of greater density, it is best to start from bare soil. To do this, spray any grass or weeds that are growing with a non-selective herbicide like glyphosate. This can be done as soon as they are actively growing in the spring. The dead weeds and grass should be mowed using a mower’s lowest setting and its bagging attachment to remove as much debris as possible. A rented power rake, electric dethatcher or scarifier can then be used to pull up rooted debris which can in turn be “vacuumed” up with the mower.
STEP #4 – Plant
Seed should be spread using a broadcast spreader and then pressed into the soil using a lawn roller. It should be topped with peat moss or a tackifier-containing mulch. The latter is strongly preferred if planting on any sort of hill or slope. Plugs should be planted using a plugger in a diagonal grid pattern either six or twelve inches apart. The more plugs, the higher the cost, but also the quicker the establishment. Sod should be laid in a brick-like pattern with its seams pressed tightly together.
STEP #5 – Fertilize
A starter fertilizer should be used when seeding or plugging. Sod most likely does not need fertilizer as it is heavily fertilized at the sod farm. Thirty days after seeding, plugging or laying sod is a good time to fertilize gain. This is also a good time to apply humic acid and sea kelp.
STEP #6 – Water
Seed should be kept moist until it germinates. A hygroscopic product can be applied to help with this. Plugs and sod should also be regularly watered for the first three weeks. Watering can then be adjusted to become deeper and more infrequent.
STEP #7 – Prevent Weeds
As mentioned above, weeds should be kept out during the establishment period. Tupersan, a pre-emergent herbicide, can be applied when plugging. Four to eight weeks after seeding, plugging or sodding, a good quality, three-way or four-way herbicide like Trimec Southern should be sprayed to kill broadleaf weeds that are present.
Caring for Zoysia
Mowing. Most varieties of zoysia are best kept at 1.5 to 2 inches in height during the growing season and then allowed to go up to 2 to 2.5 inches during the fall. As with all grasses, mowing should be done regularly enough that no more than one third of the grass blade is removed during any one mow. The idea that zoysia could be mowed once a month is imaginative, at best, but it does grow slowly and will rarely require to be mowed more than once a week.
Watering. Zoysia is drought tolerant but will lose its color if not watered enough during the growing season. It will require roughly three quarters of an inch of water during the spring and fall and an inch during the summer. If rain does not provide these amounts, supplemental irrigation will be required.
Fertilizing. Zoysia requires between two and a half and four pounds of nitrogen per year per thousand square feet of grass. It will also require an adequate supply of phosphorus, potassium and various micronutrients. Fertilizing should be done in accordance with a yearly soil test and with the bulk of any nitrogen applications taking place from May through August.
Dethatching. Even when handled correctly, zoysia will produce a thick layer of thatch that needs to be removed. Liquid dethatching can be helpful but a full, mechanical dethatching should still be done with a verticutter or power rake once per year, preferably in the late spring or early summer.
Manage weeds. While zoysia will squeeze out many broadleaf and grassy weeds, some may still show up. Most of them can be killed Trimec Southern, the same herbicide suggested above, or any similar product. Zoysia’s most difficult invader might be what populates your neighbor’s lawn: bermuda. Keeping bermuda out of zoysia will require a professional-tier product like fluazifop (Fusilade II) or fenoxaprop (Acclaim Extra).
Managing disease and insects. Zoysia is certainly a hardy grass but many claims about its ability to resist disease and insects are dangerously exaggerated. Particularly in lawns in the deep south, chinch bugs can be an issue. If found to be present, an insecticide should be applied. The most common and deadly disease in zoysia is Large Patch. When planted in soils that are less than well drained it will be be particularly susceptible. In lawns that have these soils or in areas where Large Patch has appeared in the past two applications of the fungicide Azoxystrobin, one in mid-August and one in mid-September should be applied to prevent it.
Do not overseed. In southern areas the temptation to overseed dormant zoysia with rye so as to have a green lawn year-round is surely quite high. However, while this technique works well on bermuda, it doesn’t work on zoysia. For one, a healthy zoysia lawn is generally too thick to allow much rye to get through, even when dormant. Second, and more importantly, the stress this overseeding puts on zoysia is dangerous and can lead to problems during the following season.