Cover Story

Centipedegrass Revisited

By Jay McCurdy, Mississippi State University

A prior article, The Centipedegrass Conundrum – Holistic Approaches to Weed Control by Jay McCurdy and Michael Richard was published in 2018 and has been updated here with new information.

Centipedegrass has become perhaps the most common lowmaintenance turfgrass species in the southeast. We can think of no other that has the breadth of utility in poor soils and areas with infrequent care. Unfortunately, its finicky response to routine maintenance means it sometimes gets “loved to death” by those responsible for its care.

Centipedegrass was first introduced in 1916 from Southeastern Asia. Seed were collected by the plant explorer Frank Nicholas Meyer (the namesake of ‘Meyer’ zoysiagrass and the ‘Meyer’ lemon) who was employed by the USDA’s Office of Seed and Plant Introduction. He drowned somewhat mysteriously near Shanghai in 1918 while exploring southeastern China via the Yangtze River.

There are at least eight species within the genus Eremochloa. Centipedegrass (Eremochloa ophiuroides) is the only one cultivated as a turfgrass species. Centipedegrass has many other common names. Chinese lawngrass or China grass denotes its origins. It is called cemetery grass due to its prevalence within cemeteries and poor man’s or lazy man’s grass because of its low maintenance requirements.

Centipedegrass is a warm-season, lime-green, medium-textured, slow-growing grass found throughout the southeastern United States as low-maintenance turf. It persists in humid-subtropical and tropical climates. Centipedegrass persists as far north as Tennessee and coastal Virginia; although, it is easiest to maintain where winter-time temperatures are mild. Centipedegrass is one of the least drought-tolerant warm-season turf species. For this reason, it tends to do well in gulf-coastal environments due to timely rainfall during peak summertime temperatures.

FIGURE 1. Centipedegrass injury due to drought conditions in the fall of 2016.

Centipedegrass varieties include ‘common,’ ‘TifBlair,’ ‘Oaklawn,’ and ‘Tennessee Hardy.’ Centipedegrass spreads by aboveground stems called stolons, as well as by seed. Seed take roughly three weeks to germinate and require adequate soil temperature to do so (approximately 80 degrees). Centipedegrass is commonly propagated vegetatively as sod but may also be established by sprigs or plugs.

Centipedegrass thrives in soils of moderate to low pH (between 5.0 and 6.0). Prior to establishing any turfgrass, a soil test should be performed in order to determine soil pH. Other site considerations should include shade, wear, and expectations. Centipedegrass persists in moderate shade better than bermudagrass but not nearly as well as St. Augustinegrass. Centipedegrass has poor wear tolerance and is slow to recover from injury because of its slow growth rate. Low fertility requirements and short-statured growth make centipedegrass well suited for low to no mow scenarios, but property owners expecting thoroughbred performance will be unhappy with a plow-horse trod.

Once established, nitrogen inputs should be limited to less than 2 lbs nitrogen per 1,000 ft² per year. By contrast, this is roughly half that recommended on low-maintenance bermuda and zoysia grass lawns. When using controlled-release nitrogen sources, I recommend even less. In some environments, nitrogen input may not even be needed every year.

Some of the most experienced centipedegrass gurus suggest a potassium supplement in the spring and fall. Some folks use foliar apps of iron to correct the bleached appearance of grass grown in soils where pH is above optimal. The darker color lasts until the leaf tissue grows enough to be mown. Humic and fulvic acids, as well as various other soil amendments, are frequently suggested though research is scant in centipedegrass.

Centipedegrass does not have underground rhizomes like bermuda and zoysia grasses. When over-fertilized, it becomes thatchy and prone to stress-related decline. To prevent thatch, only fertilize when grass is actively growing, which in most southeastern lawns is after the third or fourth mowing event. Centipedegrass does well at a range of mowing heights (1 to 4 inches), but it does not recover well from scalping. Mowing low according to the 1/3rd rule during growing months helps promote lateral growth. Bag clippings if they accumulate or clump together and add them to your compost.

FIGURE 2. Herbicides applied in Biloxi, Mississippi on May 4, 2015. Spray volume was 40 gallons per acre. A non-ionic surfactant was included. Photos were taken 2 weeks after treatment. Notice slight turfgrass injury results from all treatments.

New Insights in Weed Control and Fertilization

Lawn care professionals have made significant improvements in managing centipedegrass by softening their chemical weed management approach. They are using less harsh herbicide chemistry and have moved towards a lower reliance on preemergence herbicides. This is in contrast to the way we think about managing bermuda and zoysia grasses.

One approach that has improved centipedegrass quality on home lawns is the use of slow-release fertilizers, usually applied in the early spring green-up phase. Despite inadequate temperature for release, some of these formulations provide an earlier green color and generally more competitive lawn.

Without a doubt, some of the best centipede lawns are those that are mown relatively high in height of cut (approximately 2.5 to 3 inches) and relatively infrequently (usually no more than weekly during the growing season). This practice promotes healthier, denser turf, which is more resistant to weeds and other stresses.

Figure 3. A centipedegrass lawn that has thinned due to poorly drained soil. The grass in the foreground is actually carpetgrass, which tolerates standing water and wet soils.

Holistic Weed Control

Unfortunately, centipedegrass does not conform to conventional herbicide applications as well as bermuda and zoysia grasses. Lawn care professionals who manage centipedegrass well are less governed by routine schedules and make decisions based upon concern for plant health rather than pest control. They scout and spot treat problematic areas. They run routes that are focused on sensitive species—centipede, St. Augustine, and carpet grasses. And most importantly, they educate consumers about expectations and appropriate cultural practices.

The essence of weed-free centipedegrass is dense, healthy turf. Centipedegrass is highly susceptible to herbicide injury during fall and spring transition periods, regardless of labeling. For instance, auxin-mimicking herbicides (2,4-D, MCPA, dicamba, and others) are tolerated well enough when turf is actively growing, but during fall and spring transition, centipedegrass is susceptible to injury and slowed growth. Likewise, metsulfuron is labeled, but when applied during transition or even during mostly dormant winter conditions, injury and thinned stands are fairly common. When actively growing, phytotoxicity is transient, but during fall and spring dormancy or summer drought stress, even the slightest injury may push it over the edge.

Best Management Practices for Centipedegrass Weed Control:

• Prioritize plant health. Manage fertility, soil pH, cultural practices, and especially thatch if you want a resilient centipedegrass lawn.

• Mow at a height that allows infrequent mowing. The higher the height of cut, generally the less frequent mowing.

• Rely upon fall preemergence herbicide applications for control of annual bluegrass and cool-season broadleaf weeds rather than winter/spring postemergence treatments. It is fairly typical to apply low rates of mitotic-inhibiting herbicides (e.g., Barricade, Pendulum, Dimension) in conjunction with simazine at a fall timing. Some practitioners apply reduced rates of Specticle in the fall, but this is not advised unless dealing with extremely healthy centipedegrass. Ultimately, simazine and atrazine are the safest preemergence treatments for centipedegrass, but they lack the same spectrum of weeds controlled as many other preemergence options.

• With the exception of simazine or atrazine, avoid the use of preemergence herbicides in the spring. Fly-away or looping stolons in lawns treated with mitotic-inhibiting herbicides or Specticle are typical. Gallery (isoxaben) might be another exception, as it tends to be very safe on grasses. Unfortunately, Gallery lacks control of grassy weeds.

• Reduced rates of simazine and atrazine are standard recommendations for spring broadleaf/Poa control with the added benefit of some preemergence activity. For new customer accounts, a round-1 “clean-up” option is atrazine. Atrazine on a granular fertilizer carrier (e.g., Scotts Bonus S) in spring is a standard that homeowners can do themselves, but this application timing is arguably too early for application of the fertilizer carrier.

• Avoid postemergence herbicides during spring and fall periods of static growth. Even though they’re labeled, products containing auxin-mimicking herbicides (e.g., 2,4-D, dicamba, mecoprop, clopyralid, and others) can be particularly problematic during periods of transition or slow growth. Herbicides are rarely the only cause of decline, but when combined with stress, such as drought or slowed recovery from winter, they too frequently result in thinned turf or stunted growth.

• When possible, spot treat postemergence herbicides rather than broadcast applying. This can be impractical but so is resodding an entire yard.

Preemergence Herbicides Labeled for Centipedegrass:

• Barricade and others (prodiamine)

• Coastal (prodiamine, simazine, imazaquin)

• Dimension and others (dithiopyr)

• Gallery (isoxaben)

• Gemini (prodiamine, isoxaben)

• Echelon (prodiamine, sulfentrazone)

• Freehand (dimethenamid, pendimethalin)

• Kerb (pronamide)

• Pendulum and others (pendimethalin)

• Pennant Magnum (metolachlor)

• Specticle Flo (indaziflam) – Not for use in sod

• Surflan (oryzalin)

Postemergence Herbicides Commonly Used on Centipedegrass

A bulleted list fails to show the general trends in use. These postemergence herbicides are safe when applied to actively growing, non-stressed centipedegrass. Ones that are particularly safe include halosulfuron and sulfosulfuron—both of which provide good to excellent control of most sedges. Sulfosulfuron has some additional benefits in that it can suppress buttonweed and bahiagrass. But for broad spectrum weed control, we routinely include the standard of sulfosulfuron with a low rate of metsulfuron (0.25 oz/A or less of the 60 WG product) with Change Up (1 pt/A). There are lots of similar options that we hear of folks using. Just be certain you are not applying to drought stricken or diseased turfgrass during the growing season.

This may disappoint some readers, but there are no truly safe AND effective herbicide applications for broadleaf weed control during periods of transition (into and out of dormancy) and winter dormancy. We see centipedegrass death/decline for many reasons, but it is noticeably higher in professionally managed lawns than in lawns that are “mow-what-grows”. A balance must be struck in order to provide the best centipedegrass. 100% weed control should not be the sole objective.

FIGURE 4. From left to right: bermudagrass, centipedegrass, St. Augustinegrass, and zoysiagrass stolons.