I would put good money on the odds of success at 90% or better. Hydrangeas and Nandinas are both easy to grow shrubs and still dormant right now so easy to transplant. You can prune both of these shrubs down almost to the ground and they will sprout forth with new vigor in the spring. The hydrangea will not bloom the first year after a severe pruning however as flowers are borne on two-year-old branches. The exception to this is the new hydrangea variety called Endless Summer\" that flowers on new growth so can be pruned every year. \"