Pruning Shrubs

What Happens If I Don’t Prune My Hydrangea?

Panicle hydrangea in winter with beige dried flower clusters.

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

Pinky Winky panicle hydrangea with pink and white flowers.
Panicle hydrangea ‘Pinky Winky’ in bloom in late summer, with the cultivar ‘Limelight’ behind it. Photo: http://www.provenwinners.com

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 

Incrediball tree hydrangea in snow showing dried flowers.
The tree hydrangea (Hydrangea arborescens, here the cultivar Incrediball) also creates a wonderful winter effect if you don’t prune it in the fall, but you can’t prune just any hydrangea in the early spring … not if you want flowers! Photo: http://www.provenwinners.com

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. 

Larry Hodgson is one of Canada’s best-known garden communicators. He has notably been editor-in-chief of HousePlant Magazine, Fleurs, Plantes et Jardins, À Fleur de Pot and Houseplant Forum magazines and is currently the garden correspondent for Le Soleil and radio garden commentator for CKIA-FM Radio. He has written for many garden publications in both the United States and Canada, including Canadian Gardening, Harrowsmith, Horticulture, Fine Gardening and Organic Gardening. He also speaks frequently to horticultural groups throughout Canada and the U.S. His book credits include The Garden Lover’s Guide to Canada, Complete Guide to Houseplants, Making the Most of Shade, Perennials for Every Purpose, Annuals for Every Purpose, and Houseplants for Dummies, as well as nearly 60 other titles in English and French. He is a past president of the Garden Writers Association (now Garden Communicators International) and the winner of the prestigious 2006 Garden Media Promoter Award offered by the Perennial Plant Association. He resides in Quebec City, Quebec, Canada.

3 comments on “What Happens If I Don’t Prune My Hydrangea?

  1. I started working with a landscaper when I was eight years old, picking up pine cones ahead of the lawnmower in 1968.
    Every day I learned something new., not pruning heavy cut back until spring, late March, so the owner could see the full plant until just before new growth comes out. The season pruning was not the same as a harsh cut back in late winter or early spring. Good article!

  2. I cut back my Little Lime when the dried flowers start to drop off, usually in mid-winter (Maryland, zone 7). I do this to prevent all the dried flowers from littering the garden, and they do litter — seeming to make piles in corners, other plants, and hard to reach places.

  3. Wild hydrangeas probably did not bloom with such bulky trusses. They were likely able to continue to bloom as normal without pruning because they did not need to concentrate their resources. There are quite a few hydrangeas here that do not get pruned because their landscapes are abandoned. They continue to bloom, bot would likely bloom better if pruned for concentration of resources. I have renovaed quite a few. For some, the process takes a few years of pruning. Those with bigger floral trusses respond more favorably. Those with smaller trusses bloomed satisfactorily even while overgrown.

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