Chamber Bitter; Gripe Weed - Phyllanthus Urinaria

spoonbillOctober 16, 2009

My property is infested with this weed, brought in, alas, with various natives I planted throughout 21 acres. This year I decided to get rid of it, and it has been the battle of my life. I spray it with glyphosate and hand pull some of it, which is back-breaking. My question is in two parts: at what point are the prolific seeds mature? It is much easier to spray it, but I'm hand-pulling it if the seeds look mature, for fear they'll sprout even where the sprayed plant dies. The second related question is: if the seeds are immature, or mature for that matter, does spraying glyphosate interfere with their ability to sprout, such that it would be OK to spray a plant with even mature seeds and let it just fall where it dies, without fear of the seeds sprouting? Or are the seeds impervious to the hormonal disruption inflicted by spraying?

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Beeone(4 N. Wyo.)

I have no experience with this weed, fortunately by the sound of it.

However, in general, if the seed is still in the milk or early dough stage, glyphosate should pretty well kill the seeds. Once they reach the late dough stage, they are pretty much just drying down and your success will also drop, and when ripe, the glyphosate will have minimal effect at best.

To tell the stage, crush a seed in your fingers (if it is in a small pod, open the pod to get to the seed first), then squeeze it between your fingers. If it crushes to release juice, it is in the milk stage. If it releases something like batter, it is early dough stage. If it is like bread dough or drier, then it is probably too late and picking and destroying is your best option.

You could probably try spreading some Preen next spring in the areas where you had it to try to stop any seeds that did drop. Preen acts to inhibit seed germination and early root growth of annual plants and would not hurt native perennials you had planted. However, if you planted native annuals, it would likely prevent their seeds from growing next year, too.

    Bookmark   October 19, 2009 at 1:18AM
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jean001(z8aPortland, OR)

It was said "However, in general, if the seed is still in the milk or early dough stage, glyphosate should pretty well kill the seeds."

I would be cautious about trusting such action. Roundup is taken up better prior to when seed development begins -- it's usually best just before & during flowering -- so I suspect the seeds could continue to mature.

    Bookmark   October 24, 2009 at 5:39PM
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Thanks so much for the input and education about seed stages. Much of my problem has to do with the fact that I'm dealing with a fairly wild and natural 21 acres - which floods a lot, to boot. Flooding, no doubt, has helped distribute the seeds. I made the mistake of allowing the plant to grow for a couple of years, thereby disseminating thousands of seeds all over the place, figuring it was hopeless to try to eradicate it. It is clearly a process that will take several years, at best.......

    Bookmark   November 1, 2009 at 11:52AM
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