If I had a fancy collection of iffy not-so-hardy spider (or other exotic) mums from King's, I'd provide winter protection with a floating row cover (search http://www.google.com for those). Since these often bloom around November (with exceptions), I'd drape the cover over a frame built to the dimension of the mums so I could enjoy the flowers after fall frost. And I would also mulch (not on top of the crowns) after the ground freezes to help prevent alternate freezing and thawing from heaving the roots out of the ground, as well as provide a windbreak of some kind like a trellis on the windward side. Be sure your mums have good drainage. This is good to keep in mind, if planting late, too.
King's has a great essay with more information on the culture of these plants.
Hope this helps and that you'll keep us posted on what develops for you -