If I were you, I would prune the brown dying branches back to the crown of the plant or maybe 6" above the crown, (maybe someone else knows better), and keep well watered and put a fence around for the rest of the season. I'm sure there is still enough time for the plant to send up more stalks. May not get flowers next year, but maybe you will. You've still got the better part of two month of growing season left. I don't think I would fertilize though since new plants are usually over fertilized to begin with and it's a little late in the season for more. Don't forget the wire fence, whatever thought it was a delicacy will be back! Might be a ground hog too and they're persistent buggers!! Not as cute as bunnies! This is just my opinion, not the written word! Good luck,

Donna