You could add an "Uproot" ability to the Kudzu plants that lets the owner pay
to destroy them and take a damage. Then you could also have the upgraded plants be better (
to destroy and take 2 damage).
Or you could change the uproot cost to some number of unaligned quanta, in which case there'd be no reason you couldn't leave the plants as immaterial, since there would still be a way to get rid of them.