Chinese Snowball Viburnum (Viburnum macrocephalum 'Sterile')

I bought one of these at lowes and it says on tag that it gets 6-8 ft wide and 9-12 ft tall. Also says zone 3
So I am in zone 6 and I read on the MO botanical website that this shrub is only hardy to zone 6 and sometimes dies back in St.Louis area.
I am wondering if anyone can tell me anything about it, anyone have experience growing it? I don't want to plant these if it won't do well for me.

Thank you!
I'd also like to know how long the blooms last if anyone knows? Do they hang on most of the summer like the hydrangeas do? or do they fade and drop faster than that?