Hydrangea quercifolia Snowflake blooms on old wood, or wood produced the previous year. Flowers: 15 in. long white panicles that can extend upward, outward or pendulously.

If you cut back hard every year, you will not have drooping or pendulous blooms. You will not have blooms, you will be removing the wood that produces the flower buds.

Pruning makes them droop more. Older unpruned stems can handle more bloom weight as time goes on.

I would not prune oakleafs now either. Mine are starting to shut down for the year and the invisible flower buds have already developed near the end of the stems so pruning would result in no blooms or just a few. If you want to prune them. do so after they have bloomed but before the end of June.

As slow as Snowflake grows (at least mine has been slow) I cannot imagine cutting it back except for cuttings to start new plants.

Is there a reason you would want to cut it back? Drooping blooms on this plant is part of its appeal due to all the weight. Maybe you need some staking? I staked my largest blooms last year (as shown in this photo).

Oh, how nice to see a picture of a blooming hydrangea! I am already tired of looking at the dried out "sticks" of the mophead hydrangeas. At least the oakleaf hydrangeas still have leaves over here.