Containing Mexican Petunias
Q: We have a long row of Mexican petunias along our back fence that have spread far more than I like. I need a strategy to contain them.
A: It may have pretty flowers but Mexican petunia, Ruellia brittoniana, can be invasive! Personally, I dig a six-inch wide trench a few inches deep around my clump every spring. That removes any plants that have moved into the border during the previous year. If I get lazy, I spray escapees with glyphosate (KillZall, Roundup, etc) while shielding adjacent plants with a piece of cardboard.