Answer: A single climbing hydrangea is all you'll need to cover your 5 x 8 foot trellis. After planting, you'll want to give your hydrangea 2-3 years to become established and no pruning should be necessary during that time. In fact, as a rule, climbing hydrangeas require little or no pruning. If shoots grow out of bounds, reduce their length in summer. Aside from that, you can remove spent flowers if you find them unattractive.
Enjoy your garden!
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