Colquitt County Ag Report

News, events, and happenings in agriculture.

Rattlesnake Weed

 This time of year I often get questions like this from home owners. Ninety nine percent of the time it is rattlesnake weed or Florida Betony. Florida betony is a “winter” perennial and, like most plants in the mint (Labiatae) family, has a square stem with opposite leaves. Flowers are usually pink and have the classic mint-like structure. Unlike its relatives, it has the unique characteristic of producing tubers that look like the rattles (buttons) of a rattlesnake, hence the name “rattlesnake weed”.
The first line of defense against Florida betony in turfgrass is to use cultural practices that promote vigorous turfgrass growth and development. Florida betony does not readily infest turfgrass that is properly fertilized, watered, and mowed at the correct height and frequency. Florida betony is usually found in bare or thin areas of the turfgrass resulting from (a) improper mowing practices (cutting height is too low/high or turfgrass is not mowed at the correct time intervals); (b) improper watering (too much or too little); (c) improper fertilization (too much or too little, wrong date of application, wrong N-P-K ratio); (d) the use of a non-adapted turfgrass; or (e) failure to control insects and diseases.
The impact of good cultural practices on a Florida betony control program cannot be overemphasized. The amount of Florida betony infesting a turfgrass will be less if the turfgrass is properly maintained. Preemergence herbicides such as oryzalin (Surflan), benefin (Balan), pendimethalin (Halts, others) and bensulide (Betasan, others) will not control Florida betony. In turfgrass, products containing atrazine (Aatrex, Hi-Yield Atrazine, Scotts Bonus S, others), 2,4-D (various trade names), dicamba (Banvel, others), and 2,4-D + MCPP + dicamba (Ace Lawn Weed Killer, Wipe-Out, Weed-B-Gon Lawn Weed Killer, 33 Plus, others) may be used for control.
Centipedegrass and St. Augustinegrass are not as tolerant of 2,4-D and dicamba herbicides as are bermudagrass, zoysiagrass and tall fescue. Use 2,4-D or dicamba-containing herbicides only if the product is labeled for use on centipedegrass and St. Augustinegrass (some formulations containing these herbicides are specifically made for these grasses). Always apply herbicides that contain 2,4-D, dicamba or MCPP during the cool months of the year, when Florida betony is actively growing. Applications during the hot summer or cold winter months are not effective in controlling Florida betony.
Atrazine is recommended for use on centipedegrass, St. Augustinegrass, zoysiagrass and dormant bermudagrass. This herbicide is not recommended for use on tall fescue because this turfgrass is not tolerant to atrazine. Spot treatments of glyphosate (Roundup, others) also can be used to control Florida betony. The turfgrass will be severely injured or killed, however, if glyphosate contacts green turfgrass leaves.
The preferred time to treat Florida betony with sprayable formulations of atrazine (Hi-Yield Atrazien) is mid- to late October during the fall growth flush. An additional atrazine application in mid- to late February should coincide with the spring growth flush on warm season turfgrasses. Do not apply fertilizer-based atrazine products such as Scotts Bonus S to centipedegrass during late fall or late winter as applications of fertilizer to centipedegrass can predispose this warm-season turfgrass to winter injury.
Florida betony can be controlled in turfgrasses with carefully-timed herbicide applications. There is a marked difference in the tolerance of the various turfgrasses to the presently available herbicides. Read the product label to determine if the herbicide is labeled for use on a particular turfgrass species.

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