some sources say zone 3a for hardiness so your well within the range. Also, Almost Eden Nursery has them for 24 dollars if you had not checked them out already.

Can't comment on hardiness in zone 6 BUT I ordered one of those $24 'Vulcan's from almost eden last year and it did great and grew about 2' in our awful heat and drought last year. No flowers, though. The people that run the business also have very good communication and the final product I received was in fine shape root wise. I will be receiving a new order from them today, actually =). The low price point is right in my "experiment" range as long as I don't get too many going at one time...

John

Vulcan as a zone what? after that, gotta get the pacemaker checked out.

I'd not try it in any parts of z5, unless you REALLY know your specific site, or are willing to take the chance of losing it against the reward of having a truly unique specimen.

z6, should be good to go, but there may some places due to exposure, prevailing winds, where it may suffer some dieback.

The tree itself may be hardy to -10 or so, but the flower buds are not. Magnolia specialist nurseries generally give Vulcan a Z7 rating for that reason.