I transplanted several 1.5' (I assume you meant 3' not 3") plants a few years ago without much care and most survived. They don't grow rapidly so it is hard to tell about the results. I suspect I did it in the spring which is not the best time. Fall/Winter is best for allmost everything. Perhaps someone will correct me, but my plants didn't have a large root system and I imagine that even 3' plants might still be easily dug around, except for fighting with the folliage itself.

chateau..take a wider rootball than deeper.
When you dig to transplant a heavily foliaged shrub it's more important to get enough of the fine hairy roots that grow outward than the thicker anchoring roots. The fine roots are the moisture and food collectors important to maintaining the large degree of foliage.