darwin7, since no one has replied. If you have Roundup, I would use it. It is said that the surfactant in Roundup can cause a lessening of frog production. Just be careful and spray it only on the plants. Should be no problem. If you dont have Roundup, a generic glyphosate will be cheaper and not contain the same surfactant. If you just cut them, the new growth should be a 'sucker' for the herbicide application. Let us know yur results. You can also use cotton gloves and use 1/2 strength product to wipe on the reeds(leaves). It will not take much on each leaf.