You are in zone 7. Since you have had a colder and snowier than normal winter, you should probably expect it to dieback. It will leaf out mid to late spring and quickly grow new branches and flower buds. I would wait to prune it until you see how high up it has new leaves. How much I prune my crapemyrtles in the spring is different each year. It just depends on the winter. Once it gets growing in the spring, you can fertilize with compost or a slow release fertilizer. Be sure to water after fertilizing.
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