I doubt it. They're only supposed to be hardy to Zone 7, and Most of Salt Lake is Zone 5 or Zone 6 if you want to push it a bit. If you did get them to survive, I'm sure they would die to the ground each winter, so they'd be more like a small herbaceous shrub that re-sprouts if it makes it through the winter.

I have checked my zone several times from several different sources and I see Zone 5, Zone 6 and zone 6b. I am pretty sure I am zone 6. Anyway I did some searching and found the Hopi Crepe Myrtle. It is supposed to be the hardiest of the species and is supposed to grow in zone 6. But they do not get very big. I think it was about 7 to 10 feet. Has anyone ever grown a Hopi before? I am thinking about it but would need to pick the right spot.

No for most crepe myrtles, but there are a few new northern varieties you will have to get if you want success. I have a ToTo which stayed out in a pot last year and did fine. Planted it this year, but out front where it will get more winter wind - we'll see.

Sorry, that should be a Tonto (red) crepe myrtle.

There are a couple of crepe myrtles that are thriving - long term - in Salt Lake City. They are in the Sugarhouse area on 17th South and 21st East. One is on a south facing wall of the brick home on the north east corner of the intersection and is a beautiful pink color when in bloom. The other is planted on an east facing wall (kind of s.e. corner of the house) of the home on the northwest corner of that same intersection. It is a deeper more lavendar pink when in bloom. I have no idea of the cultivars but these have been growing there for years and wintering over with no other apparent protection. I would say they are about 8' tall. I always enjoy driving by these when they bloom. Makes me think of Memphis, where I first saw this beautiful kind of tree.