Almost everybody is enchanted by the large, mophead blooms of bigleaf hydrangea (Hydrangea macrophylla and cvs., Zones 4–9). And it seems that almost everybody who grows these flowering shrubs has questions about pruning them. The thought is often that, because they are shrubs, they must need to be pruned. Some gardeners also think that cutting back their hydrangea might make it bloom. Neither of these thoughts is correct. Bigleaf hydrangeas grow just fine without any pruning, and making your cuts at the wrong time can actually remove the flower buds you are hoping to get.
Bigleaf hydrangeas typically bloom on old wood, meaning the flower buds are on the growth produced the previous season. If you prune them before they flower, you will be removing the flower buds. Many newer varieties actually produce buds on old and new wood, so pruning too early doesn’t stop the whole show, just a good portion of it. But if your hydrangea isn’t blooming, poorly timed pruning is often the culprit. The best time to cut back a bigleaf hydrangea is just after it is done blooming. The shrub then has ample time to set new growth and harden off before winter.
If you do decide you need to prune your bigleaf hydrangea, this video will give you the information you need to time your cuts correctly and identify where to make them on the shrub. The only tools you will need are hand pruners and perhaps a pair of loppers to reach down into the hydrangea. Also, be sure to wear some safety glasses. You might not think they are cool, but it is very easy to poke your eye on a stem as you are trying to see down into the shrub. And a poke in the eye is never cool.
So stay safe, time it right, and enjoy your shrub.
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