Your first mistake was planting it on the south side of the house. Look at it this way, if it does survive, and THRIVE, it will want to become a big tree (even if it is marketed as a "dwarf". Also, do not assume that the SOUTH side of the house is the best for a broadleaf evergreen. That south side also liable to result in leaves burning (from the sun) during subarctic cold spells. I expect that in Zone 6b, it will survive with occasional die back of some branches and on the most sun exposed surfaces. Now, I have seen pictures of them espaliered on houses but the south side of a house is also a HOT exposure and your climate is mid-continental (and tends toward the extremes). I have a few LG's in Zone 7 NJ and most winters they are fine but in those winters of arctic vortices, they did suffer, but, they make a really, really nice and fast recovery in the growing season. I like this cultivar chiefly for its length of flowering season (try May to Halloween..., no other one that I have flowers that long), but it is not the cold hardiest cultivar. (For zone 6B, Edith Bogue, Victoria and Bracken's Brown are better choices.) I rarely see any damage on my LG;s however from heavy snow loads. You might spray the leaves in November with an anti-desicant to help with winter, sun scold.

Years ago, I planted a non-dwarf variety right next to my house (also south side), thinking it was necessary for survival. The tree was gorgeous and grew past the second story of the building (many M. grandifloras grow WIDE and tall), I felt awful when it had to be chopped down due to it massive size and ridiculous proximity to the house. However, I do not believe Magnolia roots damage structures and they tend to be very ropey and very shallow rooted, which by the way does NOT equal easily damaged by wind. Mine went through Superstorm Sandy without shedding a branch as other trees and structures crashed down around it.

I would also suggest mulching it well (helps in both heat and cold, and maintain watering if dry.

i'm located in the mount vernon area. we are closer to nashville TN then we are to chicago. there are lots of very big southern magnolias around here. and we usually don't get very heavy snows and the cold spells in winter usually don't last very long.

They actually deal surprising well with heavy, wet snows (at least the one I mentioned), fortunately, do not can ice storms really (but imagine they are worse?). BBB, I have no experience with but thy do have a good rep for cold (so that is interesting about discoloring).

we get ice storms some times and i've never seen any damage to any of the southern mags around here.

Large old southern mags are surprisingly resistant to ice and heavy snow, young trees not so much. If you are familiar with the characteristics of Bradford pear, Little Gem is considered the Bradford pear of southern mags.

interesting..