By Larry Hodgson
Question: I would like to know if pruning my panicle hydrangea in the fall is really necessary? If I leave the flowers all winter long, even after they have turned beige, what will happen to them next year? Will they fall off on their own?
Johanne Dumoulin
Answer: In nature, there is nobody to prune the panicle hydrangea (Hydrangea paniculata), the large shrubby hydrangea with dense conical clusters of flowers that are white when they open and become deeper and deeper pink as the season advances. The flowers then turn beige under the effect of frost and persist through winter or much of winter only to gradually drop off when new growth begins in spring. If ever there are still a few dried flowers left afterwards, they are quickly hidden as new leaves cover the shrub.
Personally, I never prune my panicle hydrangeas in the fall. I find their winter effect absolutely remarkable, especially in the snow. I don’t understand the logic of the people who feel the need to chop back this shrub in the fall and remove all of its beautiful flowers, leaving a bunch of brown stalks clipped off at the tip as a winter display. I figure, in the winter especially, even beige flowers are better than no flowers at all.
If you need to prune your panicle hydrangea—and it can grow huge over the years, reaching up to 15 feet (5 m) in height and spread if you never cut it back!—, you can do so in early spring, shortly after snow melt, cutting it almost down to the ground if you want to seriously reduce its size. As it blooms on new wood, the new branches that soon sprout after this early spring pruning will still bloom perfectly from late summer on and thus ensure another fall of beauty.
Every Hydrangea Is Different
Note that the information above applies specifically to the panicle hydrangea (H. paniculata). We grow several other hydrangea species in our gardens and when and how we prune them varies considerably from species to species. There are some you can also prune in either fall or early spring, like the smooth hydrangea (H. arborescens), but others you can only prune immediately after they bloom. Read When Should You Prune Your Hydrangeas? for more information on how and when to prune the various hydrangeas.