Answer: You didn't mention whether or not you've been pruning your shrub. The new foliage is pink and matures to a variegated white and green. If you do not prune in the spring, all the new growth will be at the top of the plant and you'll barely detect any of the pink coloration. I'd suggest pruning your shrub back by about a third each spring, just before new growth begins. This will result in a flush of new growth. You can also prune during the growing season to encourage more new growth (which will start out pink) and will help keep your willow compact in size and full of variegated foliage.
Enjoy your garden~
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