Hydrangeas are wonderful shrubs for the shade but they do need at least half a day of sun to flower. If your hydrangea gets sun but still does not bloom it maybe due to cold spring weather. A late frost can nip the flower buds as they form leaving only the green leaf buds. If you live in a cold climate try growing the hardier Mountain hydrangeas or the cold hardy Invincibelle line of hydrangeas that are hardy to USDA zone 3. Don't feel bad about replacing a shrub with beautiful green leaves but no flowers. Life is too short to put up with disappointing plants when there are more hardworking options waiting for you at the local nursery. Keep growing, Marianne Binetti