The roots of several invasive campanula species make them particularly dificult. The smallest pieces severed from the mother plant will begin a new life as another plant. It is impossible to manually remove all the roots. Any plant with a large root system will require multiple applications of Round up. When the poison is taken in, it is eventually distributed throughout the plant and roots. If there is a lot of root mass, the concentration of the poison becomes lower than the threshold needed to kill the plant. That is why one often sees a hard to kill plant sprayed with Round up go downhill at first, then seems to perk up in a week or two. More of the poison (a second application) is then needed to reach the killing concentration threshold. Remember you need to apply all chemicals according to directions, or you can't expect them to work as claimed. Doubling up on the Round up in one application will not work, and is a very bad idea to toy with anything that one does not know the consequences of.
Is light deprivation an option?
