I have 'Covey' which is one of the parents. It looks to have survived the coldest winter in 30 years. It was exposed to limited winter sun. Worth a shot in zone 5b.

whaas - Sounds promising. Where are you located? Somewhere outside Milwaukee County? Do you have any Oakleaf Hydrangas? I'm a bit concerned for mine.

I'm in Washington county so likely northwest of you.

My Oakleaf Hydrangeas where a failure even in the mild winters we had. I don't think they like my sandy loam which gets on the dry side throughout summer. I only had a Little Honey survive because it was in a moist location and mostly shade.

Still isn't exposed for to check it yet.

They are otherwise hardy around here just need the right spot. I've seen plenty old specimens.