Q.container crepe myrtle
will crepe myrtle tree survive in a container outside winter months in zone 6?
There are several varieties of crapemyrtle that will survive in ground in your area. In container they will likely survive as well, however, if you are concerned about those really cold nights, then You could also bring them inside if they will fit. Otherwise, put them next to a south facing wall, or mulch them well. Here is an article for more information: https://www.gardeningknowhow.com/ornamental/trees/crepe-myrtle/tips-to-grow-crepe-myrtles-in-containers.htm