Return to the Dahlia Forum | Post a Follow-Up

 o
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:

 o
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.


 o
RE: Weed Killer

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


 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!


Return to the Dahlia Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.


Learn more about in-text links on this page here