Answer: Your hydrangea sounds like it's getting the right amount of shade/sun, so as long as you're not using a fertilizer that is too high in nitrogen, the problem is probably your winter weather. Cold damage is the most common reason this type of hydrangea fails to bloom. You didn't mention whether or not you cover your Nikko in the winter. Although they are usually rated to zone 4 or 5, Nikkos (especially when young) should be given winter protection. You can do this by surrounding the shrub with a cage made from chicken wire and filling it up with leaves or straw. The Nikko Blue blooms on old wood so pruning it can also be tricky. Flower buds usually form on the stems sometime between August and October, so most gardeners prune them by the end of July. Later pruning puts you at risk for cutting off next year's buds. Fortunately, if Nikkos are located in a fairly protected area, pruning usually isn't necessary for this type of hydrangea unless you need to rein them in or revitalize them. Dead stems can be removed anytime. Good luck!
Q&A Library Searching Tips