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Weed Killer

Posted by rainydaywoman_z8 OR (My Page) on
Sun, Jan 1, 12 at 22:19

During my "Tropicalesque" garden period, I planted petasites in a raised bed so I could have large tropical leaves. So now I have petasites everywhere; they are very invasive. My question: I've read to never plant dahlias in soil with weed killer. I would like to use Roundup or its equivalent now to kill the petasites (they are runners from tubers and almost impossible to dig out). If I used weed killer now, would it be inactive by May, when I would plant dahlias? I'm planning a whole new large bed of nothing but dahlias. The rainy season has started here in Oregon, so that might help diffuse the weed killer. Or would it inactivate it? Any thoughts?

Follow-Up Postings:

RE: Weed Killer

Round up has no residual effect on the soil and is inactive within days of spraying. You can spray it before you plant dahlias but it must be done in the Spring when weeds are starting to grow. I have sprayed it a week before I tilled and planted dahlias. Weeds do not look very dead at one week but they are definitely goners.

RE: Weed Killer

Thanks for your input. Now I feel more confident. BTW: does anyone want petasite starts before I murder them all?

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