I had a rambling rose that unfortunately got poisoned. (Dont ask ).It was a very overgrown rose. Alot of the stems and part of the bush has turned brown and can be cracked off since the poison. In parts of the bush it has been cut down to a foot off the ground. Do I cut the rest of the rose bush down to this level ? Also, just wondering now if there is any hope of reviving this rose and what should I do ?