There might be an acceptable solution to the round up problem. I have done this several times but not when rain is in the near forecast. Take a paint brush or sponge brush and paint the full strength RU onto the leaves of the unwanted plant and it will absorb it into the roots only and the other plants nor the soil will be effected. After it dries you can lay clear plastic over it if you are worried about the critters. As for the rose of Sharon, that is a shrub? Dig it up.
