Lawn care: The dirt of zoysia grass

Zoysia Grass Shutterstock 259673978

A grass native to Asia, zoysia grass was introduced to the U.S. in the late 1800s and has a number of tolerances that has allowed it to thrive both in yards and on fairways across the country.

This warm-season grass creates a dense carpet of green that can tolerate heavy foot traffic and can handle light shade better than other warm-season grasses like Bermuda grass.

“Zoysia has exceptionally good winter tolerance, excellent summer performance, good density and limited pest issues,” says Zac Reicher, Ph.D., Bayer Green Solutions Team.

It can do well in the Southern zone, yet its true niche is in the transition zone, thanks to its cold tolerance that other warm-season grasses lack.

“Farther north than the transition zone, cool-season grasses perform better whereas Bermuda grass and other warm-season grasses perform better south of the transition zone,” Reicher says.

Reicher adds that zoysia is much better adapted for golf course fairways than for lawns. He stresses that while zoysia has cold tolerance, it should not mistakenly be grown in regions north of the transition zone where it will be outcompeted by both cool-season turf and weeds.

There are three main species and all zoysia grass varieties are one of the primary species or a hybrid of the primary species. It’s important to determine which species and cultivar you are working with, as each has its own cold tolerance, texture and growth rate.

“The most common cultivar of zoysia is ‘Meyer’, which has been around for 50+ years and performs exceptionally well, thus it is difficult for new cultivars to make a dent in the market,” Reicher says.

Zoysia japonica is the most common species of zoysia and it has exceptional cold tolerance. Its leaves are coarse and light green in color. Zoysia matrella has finer blades than the Z. japonica and come from Manila, allowing it to tolerate hot, humid weather. It is less cold tolerant and a slower grower.

Zoysia tenuifolia has the finest grass blades of the three but also the lowest cold tolerance of zoysia grass. It has a puffy appearance and tends to be used more as an ornamental grass in certain settings.

Some of the newer cultivars on the market are ‘Zenith,’ which can be grown from seed, and ‘Innovation’ from Kansas State University, according to Reicher.

Zoysia is typically established with sodding or plugging. It grows slower than some other turfgrasses, so make a point to communicate this with clients who may become impatient. It is best planted in the spring after the threat of frost has passed.

Maintenance needs

When it comes to caring for your client’s zoysia grass, it is not a particularly thirsty turfgrass compared to others. It is drought tolerant, needing about 1 inch of rainfall or irrigation per week. Deep, infrequent watering encourages deep roots that will handle drought better.

During dry periods or if it is grown in sandy soils, it will need more frequent watering to maintain its color during the summer.

As for mowing, because it is such a slow grower, you may not need to mow as frequently but you should never cut more than one-third of the leaf blade at a time.

“Unlike cool-season lawns that thrive with 3-4” mowing heights, zoysia performs best at 1-2” height of cut,” Reicher says. “This can be problematic, as most professional or residential equipment does not mow well at lower heights. This is another reason why zoysia is much better adapted for golf course fairways than for lawns.”

Established zoysia grass lawns need less fertilizer than other types of turf, typically needing only about 2 lbs. N per 1,000 sq. ft. a year applied in the summer, according to Reicher.

Excessive fertilizer can result in more thatch, fewer roots and diseases. Applying too early in the season causes premature topgrowth before the roots begin to grow and applying in the fall can interfere with the turf’s hardening before winter.

Common problems to watch for 

Zoysia is, thankfully, resistant to a number of turfgrass diseases, including pythium, brown patch and dollar spot. All three of these diseases are problematic in cool-season turf grown in the transition zone. Zoysia is also unaffected by spring dead spot, which targets Bermuda grass grown in the transition zone.

“The only significant disease of zoysia is large patch, formerly called zoysia patch until it was found in other warm-season grasses,” Reicher says. “It can be controlled in the fall with two preventative applications of DMI fungicides like Armada 50 WDG. If the disease is not preventatively controlled in the fall, it will form large rings of thin turf in the spring, which are unsightly and susceptible to weed infestation.”

As for weeds to watch for, the main invaders in a zoysia lawn are actually Bermuda grass and annual bluegrass.

Reicher suggests controlling bluegrass with a preemergence herbicide like Specticle FLO applied in September. On the other hand, Bermuda grass presents a greater challenge and multiple applications of non-selective herbicides like Roundup or a selective herbicide like Acclaim Extra can work.

Zoysia grass doesn’t have a lot of issues with insect pests, but Reicher says billbugs can occasionally cause damage.

This warm-season grass is prone to thatch accumulation thanks to its thick growth habit. It should be detached when it exceeds ½ in thickness. If it is over 1 inch in thickness, do not try to remove it all in one year but remove thatch over the course of several years. Aeration and dethatching should be conducted in the spring to give the zoysia grass time to recover during its peak growth season.

Common mistakes to avoid

While it may take a while to get a zoysia lawn established, it is not something to install on a whim. Zoysia is near impossible to remove once it’s settled. Before going through the trouble of getting a zoysia grass yard growing for your customer, make sure they understand they are committing to it for life. It is also known to creep into flower beds and other’s yards.

“Frankly, zoysia is considered a weed in most lawns and a common mistake is trying to control zoysia with only a single application of a non-selective herbicide like Roundup,” Reicher says. “Zoysia is difficult to control, requiring 3-4 applications on 21-28-day intervals starting after green-up. It may take two or more years of Roundup applications to successfully remove zoysia.”

Another common mistake when it comes to taking care of zoysia grass is the fertilizer rate.

“The most common mistake that I see LCO’s make with zoysia is to treat it like a cool-season turf, with fertilizer applied at the wrong time of year and at rates too high for zoysia,” Reicher says. “This is common in most areas because zoysia exists usually as patches in a cool-season lawn or is the dominant species in a handful of lawns in a route of otherwise cool-season lawns.”

Zoysia lawns included in lawn care routes that serve cool-season lawns requiring 3-5 lbs. N per 1,000 sq. ft. a year applied primarily in the fall can result in thinning or excess growth of zoysia, leading to excess thatch in turn.

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