How to get rid of Mexican petunias?

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I have a bed that they are taking over. I have tried each spring to dig them up .They come back even worse than before. I don't want to dig them up or use Round Up.
  9 answers
  • Janet Pizaro Janet Pizaro on Aug 31, 2016
    The only other way is to try and smothering them with heavy black playtic or a lot of newspaper.However I do not know if it will be enough without using chemicals. If there is nothing else around that flower bed you can try the vinegar,water,salt and dish soap.

  • Judith Judith on Aug 31, 2016
    One of the natives in our area said that her grandmother used boiling water. You would have to make sure that you poured it on only the plants you wish to eradicate. The plastic layer sounds like a safer plan!

  • The seeds can lay dormant for years! So using black plastic to cover and to cook the soil until spring. Then if you are going to plant plants then use cornmeal or the commercial PREEN to kill off any weed seeds that may have not been destroyed. good luck

    • See 1 previous
    • I hate to be the bearer of bad news but using plastic and weed barriers are the worst things to use in a garden bed. if you use any cornmeal or PREEN this will kill your bluebonnet seeds or any other seed that falls. Use the cornmeal as a dusting on the ground. this has also said to get rid of ants too. but it does not kill weeds only the seeds and after a rain you may want to put another application throughout the summer. So to avoid killing your bluebonnets you are going to have to hand pull your weeds. But word of advice for future gardens- do not use cloth barrier because the weeds just grow up through it and the roots become entangled and it does not really stop weeds but it will stunt the growth of any plants.

  • Charly Charly on Aug 31, 2016
    Unfortunately, the Mexican Petunia is a very invasive species and they are almost impossible to get rid of. You have to cut back the flowers once they are spent to stop them from reseeding. Pull out each stem gently but firmly to release the roots from the soil. Or you can cut each stem down to the ground and spray glyphosate onto each stem. This is a Systemic plant killer which means it will travel down the stem into the roots and kill the plants. Be careful that you don't spray it on any surrounding plants as it will kill them also. Mexican petunias are as invasive and hard to get rid of as Morning glories. It can be done but you have to keep at it. Good luck.

  • IFortuna IFortuna on Aug 31, 2016
    LOL People pay good money to have these. I would love to have these or Morning Glories in my yard. I had MG in California and they completely covered a pergola in front of the cottage making a nice secluded spot to read, have lunch or dinner. : ) Maybe you could put them to good use in this way. : )

    • See 1 previous
    • IFortuna IFortuna on Sep 02, 2016
      We never had that problem. The MG stayed contained in the one spot. It was an older cottage in Venice, CA and it was nice privacy from the street and when the weekend beach goers would come and park there because it was only a couple blocks from the beach. I am surprised that they ended up all over the yard. I guess a landscaper might help you with it. : )

  • Charly Charly on Sep 01, 2016
    Most people don't know what they're doing when they purposely plant either of these plants. They don't know just how invasive they can be. All they picture in their mind's eye is this pretty little vine with pretty little flowers on it. Trust me I know, because I was one of those people. I will never plant morning glories again!

  • Kid Kid on Sep 01, 2016
    Preen and or corn gluten does not kill seeds it emits a chemical that prevents seeds from germinating its called allelopathy Sunflower seeds do the same thing.

  • Betsy Betsy on Sep 01, 2016
    If you can, get a foam brush and paint the leaves and flowers with a weed killer. The plant should take the toxin to the roots and kill the plant. This is how you kill poison ivy, too. It may take a year or so because of the dormant seeds. I have Snow on the Mountain and it's over at the neighbours across the street. Talk about invasive!

  • Ysabella Ysabella on Nov 22, 2019

    so pretty much all you have to do is scream Trump and say you're going to take away their green card. In this case like Ysa, all you have to do is tell her to back.