Chamberbitter: Summertime Weed
By now, most gardeners have encountered some type of annoying weed that seems to multiply during the summer months. One weed of major concern is a weed that commonly goes by several names that include gripeweed, leafflower, or little mimosa, or false mimosa. If you guessed chamberbitter as the culprit, then you would be correct. Chamberbitter (Phyllanthus urinaria) is an annual, broadleaf, and warm season plant in our region that reproduces quickly via seeds found on the underside of leaves and branchlets.
Growth occurs in an upright formation and has a well- developed taproot system. The leaves are arranged in two rows on the branchlets and are thin and oblong, with smooth margins, resembling a mimosa seedling.
Management of this weed works best with a variety of control options that include chemical, mechanical, and cultural practices.
Mechanical Control
Hand pulling when these weeds are small is the best option. With a limited root system, they dislodge easily and can be controlled with minimal effort. Damp soil will help root dislodgement and removal, thus making the job run smoothly. This early weed removal also limits the number of mature weeds present and thus reduces the overall population of the weed.
Cultural Control
Cultural control practices help to reduce or eliminate the number of seeds that have the ability to germinate or grow. Prevention of weeds through proper lawn management practices such as properly mowed turf, application of mulch, and correct watering practices can significantly reduce weed populations.
A good layer of mulch applied at 2-3” thick during the early spring season will minimize weed development. Because these weed seeds need light for germination purposes, mulching greatly reduces viable weed seeds.
Chemical Control
Preemergent Herbicides
These products work to prevent seedlings from developing. They are an effective tool against annual weeds. The drawback is that they will not be effective on weeds that are already established, so timing is critical with applications being made before seed germination.
Atrazine can be used as a preemergent herbicide. If weed occurs in St Augustine lawns, this product can be utilized early in the season with no harm to lawn grass. Treat areas where chamberbitter weeds were frequent the year before for best results. Avoid use of atrazine in areas where food production may occur such as garden areas.
Isoxaben is a preemergence herbicide that is effective for chamberbitter control in centipede grass, St. Augustine grass, bermudagrass, and zoysia grass lawns. Make the first application in late spring and the second about 8 weeks later.
Postemergence Herbicides
Postemergence herbicides are most effective when applied to young weeds. For postemergence control of chamberbitter in St. Augustine grass and centipede grass lawns, atrazine is recommended. It has both preemergence and postemergence properties. Make two applications spaced 30 days apart.
On bermudagrass, and zoysia grass lawns, repeat applications of three-way herbicides that contain 2,4-D, mecoprop (MCPP), and dicamba can be used to control chamberbitter. Apply these herbicides in late spring or early summer when the weeds are still young. Temperature restrictions are in place on this product when temperatures reach the mid to upper 80’s. It can make St Augustine lawns look sick and cause them to stress when used with warmer temperatures.
Glyphosate – (non-selective herbicide) can also be used when needed. Spot treatment of affected areas can be used for control of heavy infestations of this weed. Glyphosate will move through the plant and into the roots to kill the entire plant. Buy a 41% glyphosate concentrate and follow label directions for mixing a 2% solution to spray in a pump-up sprayer.
With an integrated approach to weed control, chamberbitter does not have to overpower a yard or landscape bed and disrupt a landscape with unwanted weeds. As always, when using any herbicides in the landscape, be sure to follow all labeled directions for product usage.
David Oates
CEA-Horticulture Jefferson County
TX A&M AgriLife Extension Service
409 835 8461
All documents require Acrobat Reader to view them. Click HERE to download and install the FREE reader.
Soil Testing Forms for Gardens and Yards: http://soiltesting.tamu.edu/files/urbansoil.pdf
Click on the link title below to view it:
Aggie Horticulture
Gardening information and more!
Aggie Turf
Find answers to weed and disease problems, fertilization questions, how to take and submit a soil sample and much more!
E Nature – National Wildlife Federation
Illustrated site of native plants, snakes, spiders, birds, and more!
Entomology
Find information about insects
Fire Ant Management
Information on management of fire ants
Soil and Crop Sciences
Information on soil, testing and turf care
Texas Master Gardeners
Texas Master Gardeners State Association web page
Best Trees, Shrubs, Vines and Ground Cover for the Golden Triangle
A brief list of trees, shrubs, vines and ground cover specifically for the Golden Triangle area.
Ground Covers for Jefferson County
A list of ground covers that do well in our area
Growing Herbs in Texas
How to grow herbs
Homeowner Pecan Care
Care of pecan trees
Jefferson County Vegetable Gardening Guide
Large Trees
A list of large trees that do well in our area
Medium to Large Shrubs
A list of medium to large shrubs that do well in our area
Perennial Flowers
A list of perennials flowers and brief description
Pruning Calendar for Ornamental Plants
A guide to when to prune your ornamental plants
Recommended Fruit Guide for Jefferson County
Recommended varieties for Jefferson County
Small Shrubs and Dwarf Shrubs
A list of small and dwarf shrubs that do well in our area
Small Trees
A list of small trees that do well in our area
Vines for Jefferson County
A list of vines that do well in our area
