Some weeds are nuisances. Other weeds are drought tolerant, have robust root systems, and can produce seeds within the span of just a few weeks. Chamberbitter (Phyllanthus urinaria) falls into the latter category and should be dealt with quickly.
Chamberbitter’s Characteristics
Chamberbitter, commonly known as gripeweed, is a persistent and fast-growing annual broadleaf weed that thrives in warm weather. It starts growing in the early summer and is fully grown by mid-summer.
Chamberbitter grows up to two feet tall and can be easily identified by its pinnate-like leaf structure and long axils. On the underside of the axils, small white and yellow flowers appear and then grow into red, seed-dropping fruits. These fruits are often hidden by leaflets, making them hard to spot. The plant’s seeds also don’t germinate uniformly, making control even more difficult.
This weed isn’t likely to cause issues on greens and other well-manicured areas, but it can be problematic in roughs and any areas that aren’t mowed at or below two inches. This is because chamberbitter plants can produce seeds once they grow above that height. Chamberbitter plants can still cause issues on greens and fairways, though, thanks to their large taproot and unsightly appearance.
The most important takeaway is that chamberbitter grows and multiplies quickly and can last until winter, making control a top priority.
Chamberbitter Control on Warm-Season Grasses
The best way to control chamberbitter in warm-season grasses is by applying a pre-emergent herbicide. An ounce of prevention (or whatever the manufacturer recommends) is better than a pound of cure, since control will become incredibly difficult once fruits start to grow on the plant. Pre-emergents should be applied before soil temperatures reach 70°F at two inches, which is when chamberbitter seeds will begin to germinate.
Pre-emergents containing isoxaben are effective, safe choices for warm-season turf. Some powerful isoxaben options include Crew Specialty Herbicide and Gallery SC. Other options exist, like Freehand 1.75G, which contains dimethenamid-P and pendimethalin.
If chamberbitter has already emerged, product options are limited, but one stands out: Celsius WG. It is a wettable granular product that is safe to use on bermudagrass, zoysiagrass, and St. Augustinegrass. It should be used with a non-ionic surfactant when air temperatures are under 90°F to enhance its efficacy.
Control in Ornamental Areas
For ornamental areas, Snapshot 2.5TG will control chamberbitter all season long.
Chamberbitter can be difficult to control, but with the right approach, products, and guidance, you can effectively manage it on your course. If you have concerns about chamberbitter or other weeds on your course, reach out to your ATS rep. If you’re new to ATS or need a rep, find one here.
