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THE CENTIPEDEGRASS CONUNDRUM Holistic Approaches to Weed Control By Jay McCurdy and Michael Richard, Mississippi State University
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entipedegrass has become perhaps the most common low maintenance 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.
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 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.
Holistic Weed Control
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Figure 1. Centipedegrass injury due to drought conditions in the fall of 2016.
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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 labelling. For instance, auxin mimicking herbicides (2,4-D, MCPA, dicamba, and others) are tolerated when turf is actively growing, but during fall and spring transition, centipedgrass is susceptible to injury and slowed growth.
