Top tips to stop tough turf foes

Nutsedge, clover, ground ivy and wild violet are four of the toughest weeds lawn care operators face each year. To help tame and conquer these turf foes, Eric Reasor, Ph.D., Southeast research scientist with PBI-Gordon; Dean Mosdell, technical manager for Syngenta; and Aaron Hathaway, technical services manager at Nufarm, share identification and management tips.

Nutsedge often has a lime-green color and grows about twice as quickly as regular turfgrass. (Photo: PBI-Gordon)

Nutsedge

What to look for:

• Nutsedge is a grass-like plant with sharp blades, triangular stems and underground nutlets. It thrives in areas that are less fertile, poorly drained and aerated. — ER
• Nutsedge tends to grow well in sunny areas that are excessively wet. — DM

How to control it:

• It is best to control nutsedge when plants are young using herbicides with sulfentrazone. Thereafter, postemergence herbicide applications with an ALS-inhibitor, e.g., halosulfuron, imazosulfuron or sulfosulfuron, provide good nutsedge control. — AH
• Postemergence applications of pyrimisulfan provide excellent control of nutsedge. — ER
• Sulfentrazone is safe to apply on cool-season turfgrass, trifloxysulfuron is safe to apply on warm-season turfgrass and halosulfuron is safe to use on both cool and warm-season turfgrass. — DM

Keep in mind:

• The key to managing nutsedge is eliminating underground nutlets. If moving soil around, make sure it does not contain nutlets. — DM
• Develop a program for nutsedge control instead of reacting to infestations. — AH
• Apply herbicides early and make multiple applications during the year. — ER

White clover is the most common type of clover that can be found in turfgrass. (Photo: PBI-Gordon)

Clover

What to look for:

• A perennial plant that has three leaflets, a small white semicircle at the base of each leaflet and spreads by runners and stolons. — ER
• The predominant clover species is white clover, and it dominates poorly fertilized lawns. — DM
• Herbicides containing dicamba, triclopyr and fluroxypyr provide good control in cool-season grasses. — DM
• Apply dicamba, the most prevalent herbicide used, in the fall with follow-up applications in the spring. — ER
• Products with quinclorac and MCPP can provide good control of clover. — AH

Keep in mind:

• Improving lawn fertility helps control clover. — AH, ER
• For best control, apply herbicides in late summer and early fall. — DM

Ground ivy features square stems and smells like mint if crushed. (Photo: PBI-Gordon)

Ground ivy

What to look for:

• Ground ivy is a creeping perennial plant that spreads by runners and stolons. It has square stems, circular leaves with wavy edges and a notch where the stem meets the leaf. — ER
• Ground ivy has purple flowers, a minty odor and can be found in shaded areas where turf is not heavy. — DM

How to control it:

• Using herbicides that contain triclopyr or fluroxypyr will provide good control. — AH
• Fall applications of triclopyr are the best option, followed by fluroxypyr and combinations of these active ingredients with 2,4-D, dicamba and sulfentrazone provide good control of ground ivy. — ER

Keep in mind:

• Scouting for ground ivy is important as LCOs can mistake it for wild violet. — ER
• Having a good management program will make it easy to control ground ivy. — AH

Wild violet, like ground ivy, can be found in shady areas. Both weeds have purple flowers, making it easy for LCOs to misidentify them. (Photo: PBI-Gordon)

Wild violet

What to look for:

• Wild violet is part of a group of perennial and winter annual plants that are “escaped” ornamental plants. Plants have heart-shaped leaves with serrated edges and purple, blue or white flowers. — ER
• Plants have violet flowers, love shaded areas and have thick rhizomes. — DM

How to control it:

• Applying herbicides containing triclopyr or fluroxypyr is the best control option for wild violet. Mixtures that include 2,4-D, dicamba and sulfentrazone will improve control. — ER
• Postemergence herbicides spiked with triclopyr will provide excellent control of wild violet. — AH
• In addition to herbicides, reducing shade or planting shade-tolerant turfgrass species, e.g., fine fescue, will help control wild violet. — DM

Keep in mind:

• This weed is difficult to control. — DM
• Fall is the best time to control wild violet with herbicides, followed by repeat applications in the spring. — AH