This year I planted some Nikko Blue Hydrangeas and a Forever & Ever Hydrangea. Do they bloom on new wood or old wood? Should I cut them back, so only new wood would be present next year or leave them be? They are not very large now.
To cut back or not to cut back Hydrangeas
The Nikko blooms on old wood. The Forever & Ever blooms on both old and new wood. If your zone is 6 or warmer you should be OK with both, meaning normal cold winter temps shouldn't kill the flower buds. If you cut back a hydrangea that flowers on old wood you cut off the flower buds for next year. On the remontant type you should get flowers on the new wood, new wood being wood produced that same spring.