We have a very large garden filled with vinca minor which we want to remove to make room for a vegetable garden. Last summer and fall we sprayed the are with roundup a couple times until all signs of life were gone. Now that spring has sprung, we see lots of signs of life and feel we need to just pull the crowns and roots out. Will this be the end or does vinca re-sprout from tiny bits of roots left behind? Thanks!