I grow it here in what is equivelent to your zone 4a. I have had it for several years and it does well.

I have been growing this cv for 13 years and it has survived my freeze/thaw winters with no problem. I do not mulch or protect it. It gets to registered height but bud count is only about 6 on 2 way branching. It is not a fast increaser but it is a beauty so I keep it. One of my favorites.

I see that this is an old query but I also grow Destined to See in a cold zone (4b) and have grown it for many years. See my photos under celestialrose. My clump is enormous and grows in a border by the roadside and I do not winter protect at all. I live at an elevation which has quite a bit of wind and snow and yet it never suffers any dieback, is vigorous and blooms very profusely. It's one of my best bloomers.