Answer: Your big leaf hydrangea will produce blooms on new growth that develops from old wood. Hydrangeas are generally pruned back at the end of summer, after the blooms are spent. It's safe for you to prune it back now. For best growth and bloom, prune the older stems down to 18"-24" from the ground. New wood will develop next spring, and new blooms will open at the tips of the new branches next summer.
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