Hello everyone,

A weed that I believe to be chamberbitter (Phyllanthus urinaria), aka "Mimosa Weed", is absolutely destroying my back yard and is now spreading through parts of my front yard and ornamental landscaping areas. Entire swathes of my back yard are now overrun with this weed and it is starting to make inroads in the front yard at an alarming rate.

I first took note of the infestation in mid-June. I originally mistook them for seedling mimosa trees, because I have some of those on my property, but I soon realized my mistake.

Since then, I treated both yards with Spectracide Weed Stop for Lawns (sprayable concentrate that screws onto a garden hose), which is supposed to be effective on this weed, according to the label. I applied it after measuring my yardage and think it was an adequate application, but all I saw was some mild yellowing of one or two locations. There has been no appreciable die off of the weed and, in fact, it is spreading almost daily it seems. I thought I'd see quick results since I applied the herbicide a day or two after a fresh lawn cutting and prior to any heavy rain, but not so much...

I'm going to try another application of the Spectracide, as I have read that it may take another application to affect this weed, but I want to reach out to this community to ask for help. What else can I do? I know the plant thrives in this humid, hot environment and that once it goes to seed, there is little to be done (every plant is covered with seeds under each leaf...) until colder months, when the strategy should be to inhibit growth in the spring by application of some isoxaben , then treat spot areas. Problem is, we are still several weeks away from appreciably cooler temperatures here in SE Alabama and I'd like to halt this invasion before it really takes a toll on my front yard as it has in the back.

I know I'll probably spend another spring/summer season battling this weed next year when new seeds try to grow, but I'd sure like to be more effective NOW, if possible.

Any advice as to products I can use now, as well as sound practices for next year would be appreciated.

Sincerely,

D

Chamberbitter is difficult to control with over the counter herbicides. Heck, it's difficult to control, period.

Generally speaking only a few pre-emergence herbicides are effective, and as the name implies they need to be applied in early Spring, before chamberbitter seeds sprout. On the Gulf Coast this usually means April.
The active pre-emergence principles known as effective on chamberweed are flumioxazin, isoxaben and oxyfluorfen. Take note and see if they make economic sense.
Glyphosate is also effective, but as indiscriminate post-emergence herbicide it will literally kill (almost) everything: it may make economic sense to kill everything there and reseed the lawn, perhaps in conjunction with pre-emergence herbicides. Hand weeding is, obviously, out of question for such a serious infestation.

One important thing you should do now is to do your utmost to prevent those chamberbitter from going to seed. Mowing the lawn at the lowest setting may help there.

Hey, neighbor! This horrible weed IS taking over. I don't care what is growing in our mowed area, but it has taken a lot of my time to pull these out of cultivated areas. It's an annual, luckily, but every one of those seeds will sprout next year. You may have noticed that when this plant is topped by mowing, it goes into horizontal mode. For now, aim the chute away from cultivated areas so the seeds stay in the mowed area. Agree, it seems like April would be the best time to apply pre-emergent 'cide if you want to use 'cides.

The infestation starts off so subtly, but it is an insidious weed and I'm astonished to see how quickly it can turn a southern lawn into a very unpleasant landscape. At the time of this writing, I just finished application of a second round of the Spectracide, as per the instructions (indicates two applications, 10-14 days apart, during warm weather). I saturated the most infested areas in my back yard, throwing caution to the wind. If the grass dies, it won't be much worse than what this weed is doing...

In any case, My focus is on slowing the spread through the summer and fall. I pick individual weeds from around my landscaped plants and flower beds, when I can, but every time I do, I'm sure more of the seeds drop off...

ElPolloDiablo: I'm definitely going to invest in one or two of the per-emergent treatments this winter and start putting those down at the end of March or early April. Cost isn't a factor. I'm willing to spend money to save money if that makes sense. So far the front yard isn't too bad, but my back yard is a war zone and I'm getting ready to execute the scorched-earth option...

PurpleinOpp: howdy neighbor! Greetings from Enterprise! I live on the north side of Enterprise, heading out toward New Brocton. Are you aware of any kind of community gardening events or clubs in our area?

Cool, we really are neighbors! Glad to "meet" up with you. I do not know of any beyond MG program and related activities like Trail Masters group that helps with the little state park here in Opp. They do stuff during the day so I've not been able to participate but my mom did for a few yrs.

I'm trying to put together a plant swap for FL panhandle area for 5/15. Not sure if it will pull through, but there seems to be more gardeners to the south of us than around LA area. ...and it would be so much easier to stop by the stores down there... I started a discussion in the FL forum because the few times I've tried to organize a more local swap, nobody responded and it seems like there's a better chance of gathering FL panhandle folks than LA folks.
https://garden.org/thread/go/1...

On another forum site that used to be good but is now overtaken by some kind of home improvement site, they used to hold at least 1 swap per year in north AL, too far for me to want go there and back in 1 day.

There are a few other members nearby but not necessarily active in the forums I visit. Larry (Seedfork) is near you and he has some gorgeous plants, especially daylilies. You can see nearby members by clicking "memberlist" at the bottom, enter your ZIP code:
https://garden.org/users/membe...

SE is the best match for a non-FL regional discussion:
https://garden.org/forums/view...

I'm sorry, I can't help anymore with the lawn. I hate grass and mowing and wish our whole property was a beautiful patio except for the (as yet imaginary) pool and (as yet imaginary) built-in planters around the inside of the (as yet imaginary) surrounding garden wall... that keeps the grass out.