Pruning Shrubs Trees

How to Prune a Hydrangea Tree

Hydrangea paniculata ‘Limelight’ pruned to form a tree. Photo: http://www.fast-growing-trees.com

Question: I have a hydrangea tree, but its branches are too long, so when it rains, the branches and flowers bend down to the ground. Can I cut branches back and, if so, at what period?

J.Y. Simard

Answer: Sure you can prune it, but to understand how and why, it is worth explaining what a hydrangea tree is.

A Real Shrub With a Radical Bod Mod

Tree form Pinky Winky hydrangea. This cultivar is less prone to floppy branches than others. Photo: http://www.cottagefarmsdirect.com

A hydrangea tree is in fact a panicled or PG hydrangea (Hydrangea paniculata) specially pruned to take on a treelike shape. In the summer, it forms at the tip of its branches large elongated clusters of white or lime-green flowers, depending on the cultivar, which gradually become pink or even reddish through the fall. It’s pretty much the only hydrangea used this way: most other species don’t have stems strong enough to make good trees.

Normally, the panicled hydrangea grows as a large multi-stemmed shrub. It produces a profusion of branches from its base and takes on an upright, spreading shape over time, reaching up to 15 feet (5 m) in height and diameter after 15 to 20 years. It’s clearly a shrub; in its natural form, it looks nothing like a tree.

A hydrangea tree is created by pruning a hydrangea shrub so that it takes on a treelike shape. Ill.: http://www.amazon.co.uk & Crawley, http://www.cleanpng.com, montage: gardenerparesseux.com

To form a hydrangea tree, the nurseryman chooses a young specimen with a robust central branch and begins to “prune it into submission.” He removes any other branches and also secondary branches that grow on the branch selected to be the future trunk. Staking is often needed to keep the trunk rigidly vertical during the first few years. When the trunk has reached the desired height (usually about 4 or 5 feet/1.2-1.5 m), he begins pruning the top of the plant too. That forces the hydrangea to produce multiple branches at the top of a central stem: its new trunk.

And there you go! A hydrangea on a trunk, somewhat like a living lollipop!

Producing a hydrangea tree is time-consuming and adds greatly to the cost of the plant, so it’s quite a pricey item. 

You can also prune a hydrangea into a tree shape on your own if you want, but it will take a few years. 

Regular Pruning Is Required

If you want to maintain a hydrangea tree, you’ll need to be ready to prune it regularly, otherwise not only do the branches lengthen to the point they start to bend under their own weight, as you have noticed, they can even snap off, especially under the additional weight of heavy snow.

In your case, since your hydrangea tree is overgrown and the branches already bend under their own weight, it would be wise to prune it before winter. If not, there is a risk that they snap off in snowy or icy weather, so, in October or November, simply cut all branches back to about 6 to 8 inches (15 to 20 cm) from the top of the trunk.

Ideally, you’d just cut above a node (red line), not just below one, as in this photo. This will leave a shorter, less visible stub. That is, however, only a minor detail: even if you prune leaving a long stub, your hydrangea will still do fine! Photo: http://www.wsj.com

Once you’ve gotten your hydrangea tree back into a more winter-resistant shape, start pruning early in the spring rather than the fall. That’s because the dried flower heads of the panicled hydrangea have ornamental value over the winter, so you’ll want to keep them until spring.

Therefore, every year, make a habit of cutting back all the branches 6 to 8 inches (15 to 20 cm) from the trunk early in the spring, before the leaves unfurl. This will give your tree the appearance of a ball of foliage capped with flowers at the top of a short trunk, usually the desired effect. Since panicled hydrangeas flower from new growth produced starting in mid-spring, it will bloom abundantly even after a severe early spring pruning.

To maintain its treelike appearance, with a well-defined “trunk,” also remove any suckers that appear at the base of the plant as well as any growth that appears on the trunk itself. You can do this kind of pruning in any season.

Hydrangeas for Laidback Gardeners

For reduced maintenance, grow panicled hydrangeas as a multi-stemmed shrub the way Mother Nature intended. Here Pinky Winky is in the foreground with ‘Limelight’ behind. Photo: springmeadownursery.com

Giving any living plant an unnatural shape is always going to require extra maintenance, so might I suggest that the more laidback gardener might prefer to abstain from hydrangea trees and grow them instead the way they want to grow, as large shrubs. Give the plant lots of room (most panicled hydrangeas are very big plants) and just let it do its thing. Some, like Pinky Winky (‘Dvppinky’) have naturally sturdy, erect stems that don’t tend to flop, while the old-fashioned but once very popular PG hydrangea (H. paniculata ‘Grandiflora’), is huge and floppy and—what can I say?—just gorgeous even as it splays out over half your garden. If space is at a premium, there are now smaller panicled hydrangeas, like ‘Bobo’ and ‘Little Lamb’ that won’t take up as much room. And flower color, panicle size and flowering season also vary from one cultivar to the next. It’s up to you to choose the panicled hydrangea cultivar that best corresponds to your tastes and your needs!

Panicled hydrangeas grow best in full sun or very light shade in just about any well-drained soil. They’re cold hardy and adapted to zones 3 to 8.

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.

23 comments on “How to Prune a Hydrangea Tree

  1. Thank you for posting this. I was just about to post about my first year hydrangea struggles, but I am still gathering a few pictures. Your posts about hydrangeas are very helpful!

  2. For those of us who grew up with deciduous orchard trees and roses, the older types of hydrangeas are not easy to prune. We tend to prune them like what we are familiar with, which can deprive them of bloom. As much as I dislike the contemporary hydrangeas, they really are more forgiving with their pruning.

  3. Jim Campbell

    I have a tree that gets out of control every spring. It seems that the .ore I prune it in the fall or early spring, the larger it gets in early summer. What am I doing wrong? I

    • You’re not doing anything wrong. It’s the nature of the plant. Growers usually choose big, fast-growing hydrangeas to turn into trees. Of course, once you buy them, drastically pruning them every spring becomes the only way to control them. In a ideal world, the growers would only produce hydrangea trees from dwarf varieties, but it would take 2 extra years to create a saleable tree form, so they choose the easy way out. And you pay the price in heavy pruning!

  4. Gigi Reback

    I have 2 large droopy hydrangea trees. Can I turn them back into bushes?

    • Certainly, but why not enjoy this fall’s bloom and cut them back severely in early spring. You can cut all the branches back to about 1 foot (30 cm) long and that will give a nice round ball. You’ll have to repeat annually.

      • Gigi Reback

        I just came back to thank you. I did a pretty severe pruning this spring and now have big trees with lots of blooms and no sign of floppy branches.

        It will be much easier to repeat next year now that I’ve seen the results.

  5. Susan Kuckkahn

    How far back on a main branch can I cut back? Winter breakage has made my pg tree lopsided. Wondering if I can cut the main branches coming from the “trunk” of the tree.

    • You can cut back to near the base: say, to an inch or so. New growth will sprout you can then let regrow. If you cut it right off, to the trunk, there might not be new growth at that point.

  6. Hi there,
    I have a 2 year old paniculata limelight hydrangea shrub. I would like to prune this into a tree form. Is the shrub too old to prune into a tree? If not, should I prune all the branches to the level of the ground, leaving the one stem to act as a trunk?

    • What you suggest will work perfectly. You’ll have to keep cutting off unwanted branches that will sprout from the base for a while.

  7. Tracy Anderson

    I have a vanilla strawberry hydrangea that I’m in the second year of training into a tree. It’s going very well, however, I’d like it to start branching a little lower down than it currently is, if possible. Is there a method of encouraging growth lower on the trunk, or once you’ve pruned off those branches in a prior years, it’s done?

  8. Teresa Gordon

    Hello, I am in zone 5b in Thornbury, Ontario, four blocks from Georgian Bay which really moderates our climate. Can I keep my new Pinky Winky hydrangea in a large pot and store it in my unheated shed over the winter? Thank you!

  9. Judith Heingartner

    I have 2 five year old hydrangea trees that I cut back in November. I don’t know the variety but they bloom profusely with large white flowers. Since they are 5 years old should I change my pruning method or continue as usual. Thank you.

  10. Tim Mullen

    Thanks for the tips! We had a big branch from a maple fall on our 3 yr old tree, and one side was completely lopped off. Now we are left with a lopsided tree with a 3 ft trunk and several new growth branches going straight up. I was thinking of cutting off everything right back to the trunk except for one of the new branches from the top and by doing so extend the trunk up to about 5 ft, while hopefully giving it a chance to recover some balance going forward. Do you think it would it survive such a brutal pruning? Thanks!

    • It almost certainly would: shrubs are naturally resilient and panicle hydrangeas (the type hydrangea trees are made of) are particularly tough.

  11. Sherry Mohr

    I have a 10 year old strawberry panicle hydrangea which has developed about 7 2″ think very vigorous trunks which produce many new stems each year, despite cutting all stems off each fall, as well as any new branches from those 7 trunks. I haven’t had any problems with bush, except its vigorous growth and abundance of flower stems grown each year. It is beautiful this time of year but I would like to retard its growth next year. Would you recommend sawing off a few trunks this time of year? and how do I train the new growth from growing sometimes 6 ‘ long stems than hang over tree like an umbrella all way to ground?
    I’m glad I found this website and find your information very helpful.

    • You can cut even thick trunks nearly to the ground and the plant will grow back, so don’t hesitate to do so. If I were you, I’d cut back all 7 trunks come spring. If you cut really short (and repeat every year), it remain much smaller and won’t arch over.

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