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Turf School: Tips to tackle tough weeds

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White clover. (Photo: Getty Images: DNY59 / E+, boschettophotography / iStock / Getty Images Plus)
White clover. (Photo: Getty Images: DNY59 / E+, boschettophotography / iStock / Getty Images Plus)
(Graphic: Quali-Pro)
(Graphic: Quali-Pro)

Wherever clover, ground ivy or nutsedge pop up, lawn care operators must be ready and have a plan. Bobby Kerr, Ph.D., technical services manager at Quali-Pro, offers tips for identifying and treating this trio of tough-to-control weeds.

Clover

The main clover species found on lawns is white clover, which is especially noticeable when it flowers in late spring and early summer. It’s a low-growing perennial with creeping stems that root at the nodes. Its stem is smooth to sparsely covered with hairs, says Kerr.

“The flowers are white and are often found with a pink tinge and are arranged in round heads,” he adds.
Its leaves have three elliptic- to oval-shaped leaflets with small marginal teeth. It also has a small white semicircle at the base of the leaflets.

Clover is more likely to grow in patches in the lawn that aren’t properly fertilized. Improving the turf’s health, density and overall site conditions can help control this weed.

Ground ivy

Ground Ivy (Photo: Quali-Pro)
Ground Ivy. (Photo: Getty Images: DNY59 / E+,
boschettophotography / iStock / Getty Images Plus)

A creeping perennial, ground ivy is a prostrate with four-sided, square, hairy stems. Its roots are readily at the stem nodes, and the weed is arranged in groups of three to seven at the stem ends or leaf axils, Kerr says. Ground ivy reproduces from both the creeping stems and its seeds.

It has flowers that are bluish to purplish with red speckles. Ground ivy can also be misidentified as wild violet, as both weeds have purple flowers and can be found growing in shaded areas. However, ground ivy has leaves with a more scalloped edge.

“The leaves are opposite on the stem and are kidney-shaped to rounded—prominently veined and with scalloped margins,” Kerr says.

Another way to identify ground ivy is by its minty odor, which is more noticeable when crushed.

Nutsedge

Yellow Nutsedge. (Photo: Quali-Pro)
Yellow Nutsedge. (Photo: Getty Images: DNY59 / E+,
boschettophotography / iStock / Getty Images Plus)

A grass-like weed with sharp blades, yellow nutsedge grows in sunny areas with poor drainage. Its leaves are thicker than the ones on turf and the plant grows faster than most grasses. The weed is also a lighter green than most turf, which can lead to uniformity issues in the lawn if left untreated.

Nutsedge is a rapidly spreading perennial with three-ranked basal leaves, Kerr says. The leaves are flat or slightly corrugated, and they tend to be as long or longer than the flowering stem and have a long-attenuated tip.

“The seedheads are usually yellowish-brown or straw-colored,” Kerr says.

Nutsedge mainly reproduces by tubers, which are hairless, round and formed at the end of whitish rhizomes. Unlike the square stems found with ground ivy, nutsedge has triangular stems.

Control all three

Taking a proactive approach with all these weeds is important for achieving control. If left untreated on lawns, they will become unsightly and lead to customer callbacks, Kerr says.

“Earlier is better,” he says. “Trying to control mature weeds is challenging.”

Splitting preemergent applications in the fall and/or spring typically is the best approach for weed management, he adds. Improving the lawn’s fertility and reducing areas with poor drainage can also help control these weeds.

“However, these three weeds are typically hard to control,” Kerr says. “So, regular postemergent herbicide applications will be required.”

With yellow nutsedge management, it’s important for LCOs to find and eliminate underground nutlets.

“Sulfentrazone- and halosulfuron-containing herbicides are the best option for yellow nutsedge control,” Kerr says.

Three- and four-way combination herbicides with 2,4-D, dicamba, MCPP, sulfentrazone and fluroxypyr are good post-emergent herbicide options for both white clover and ground ivy, he adds.

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