I don't know if this is a problem or not. I have a double knockout rose that I planted 10/06. Last year it looked terrific. This spring it's leafed out great, but now a bunch of the leaves are dried up and falling off. I live by Binghamton and last week we had a wicked frost. I'm wondering if its frost die back. I also have a climbing rose that's OK. I've fertilized the knockout and watered quite a bit. Any advice?
Also, has anyone heard that the organization who rates our zones have changed the zone designations? Supposedly my zone is now 6.
It sounds like canker. The canes have dead spots lower down that prevent water and nutrients from travelling up the canes. Above the dead spot, the cane has enough reserves of it's own to leaf out, but not enough to keep things going. The only thing to do is to cut it off below that spot. It's usually waay down, on the underside of the cane.
The 'new' zone map has been around for a couple of years now, I think. It's been discussed. The general consensus in the northeast seems to be that if you've already decided the old zones are too conservative, keep doing what you're doing. If not, again keep doing what you're doing. Personally for me, it doesn't matter whether I'm officially zone 5 or officially zone 6. I have to plant for zone 5 either way.
