Any one have any good info on the average cold hardiness of the gisela 6 rootstock?
I spent a little time this morning but couldn't come up with anything specific.
Gisela 5 and 6 are considered very hardy. I'm not sure they are zone 4 hardy but they are supposed to be hardier than Mazzard. No damage after -18 in WA. But that's not -20 to -30 of zone 4.
With global warming, I'm not sure if Zone 4 exists at all anymore in the continental U.S. ;)
Seriously, though, Gisela rootstocks are hardy to at least Zone 5 if not Zone 4.
That is quite helpful. If hardier than mazzard it should be OK for all but the most extreme of our test winters...they certainly seem to be less of a test than they used to.
Our loss of consistent snow coer actually has me more worried about rootstock hardiness than I used to with the occasional deep dip in temp....that wasn't so bad with 20+" on the ground. Whole different story with nothing but a dusting.
Past couple of years I haven't been able to put my Gisela 5 fruit buds to the test...in 2009 (they were just very young trees then), we had -26F in Jan... they are still alive today.