I don't know... my ladyfriend in New Orleans had it before Katrina and even after soaking in brackish water for 4 weeks it came back! Very hard to kill the stuff!

Last year I bought some Shrub Roundup, fixed it real strong and hit a whole line of Mexican petunia.(about 12 feet of it.) Worked real good. This spring I have only had two or three sprouts in that area and a few more shots of Roundup finished those off.

If it worked for me it will work for you. I don't know why I thought I ever had to plant Mexican petunia anyway.

Thanks! I'm definitely getting some roundup and trying it.

hey to all who have the mexican petunia problem. i have the solution. pull them up stick them in a box and send them to me. i will plant them in my yard here in ohio, cut them down in fall and root them in water, repot them and store them in my sunroom for winter, to plant in the spring. this seems the best way to rid yourself of those darn pesky mexican petunias. i love all of them purple blue white pink short or tall.
funny how different people like different things huh? when i lived in fl i had tons of them and brought just a small handful back to ohio and i now realise i should have brought as many as i could carry as i cannot get them here. and i need ALLOT of them. so just box em up and ship them to me and the ones left behind will get scared and quit growing (you have to make sure you tell them you are shipping them up north where they will freeze to death in winter) problem solved.
email me at metoo44646@yahoo.com and i will give you the address to ship them to.

See my post on the other thread regarding Mexican Petunias. We worked four whole seasons to get rid of them by digging and using Roundup. Finally, we have not seen one this year but we are not ruling it out. If and when they do appear, we are prepared to dig and use round-up.

Ditto Patricia.