Will crape myrtle bonsai fall leaves in winter?

Yes, crape myrtle is a deciduous shrub or small tree, so it will lose its leaves in winter. It is normal for leaves to fall off. Don't worry, they will sprout and grow again in the next spring, which means you need to keep warm in winter. The winter pruning of Lagerstroemia indica can be carried out during the whole dormancy period, generally starting two weeks after the normal defoliation of Lagerstroemia indica and ending two weeks before germination of Lagerstroemia indica.