Certified GKH Gardening Expert
I would not suggest pruning your dappled willow at this time of year in Michigan. If it remains warm, the plant may push new growth that cannot be hardened off before winter and will subsequently be damaged. I would definitely recommend pruning early in the spring and then again after it's first flush of new growth to keep the plant in check. Also, be sure to fertilize as the foliage displays the best pinkish tint with a nutrient rich soil.