Questions from Customers: Hydrangea Pruning

Questions from Customers: Hydrangea Pruning

I helped a customer today who was typical of many people who grow hydrangeas. “How do I prune my various hydrangea shrubs?” she asked. “I’ve looked on the internet and it just leaves me even more confused.” Since we know that if one customer has this question it’s likely that many people have this question, here is a photo-tutorial about which hydrangeas get pruned and how to trim them. There are basically two types of hydrangeas: those that bloom on new growth that forms in the spring and produces flowers that same summer, and those that form their flower buds the summer before. The types that form their flower buds the year before carry those buds through the winter, and if those buds don’t get zapped by cold winter temperatures and wind, they will develop into flowers the next summer. Let’s call them the new growth bloomers and the second-year bloomers.

The new growth bloomers get pruned in the following way: 1. Prune these in the spring when they start to bud out and break dormancy. When this happens you can tell what is alive and what isn’t. 2. The first thing you do is to take off any dead stems and twigs. If it doesn’t have green growth on it, cut it out. 3. Next, look for any stems that are growing into the center of the plant instead of out and away from the center. Cut these out by following them back to where they join another stem, and cut them there. Leave just a tiny stub. 4. Then look for any crossed branches – if two stems are rubbing against each other this makes wounds on the plant. Find these and remove one of them by following it back to where it joins another stem or trunk and cutting it off there, leaving just a tiny stub. 5. Next, cut off anything that is weak, curvy, or odd looking, again, not leaving much but a tiny stub. 6. Remove any stems that are laying on the ground. 7. Finally, clip back any long stems knowing that where ever you make the cut that stem is likely to branch into two in that location.

The second year bloomers, which includes lace-caps and mop-heads, get pruned in the following way:  1. Prune these when the buds have started to open and you can see green leaves the size of a dime on the old stems. Note that in seasons after a cold winter you might not see any such leaves on the old stems and if this happens you can cut everything down to the ground in mid-May. 2. When you can see some stems with dime-sized leaves, prune by first removing all dead canes that have no leaves at all. Cut these to the ground. 3. Next cut off any other deadwood, moving from the top down and cutting just above the first set of leaves you come to. 4. Finally, cut out any stems that are curvy, weak or horizontal to the ground.  You can download a pdf about pruning lace caps and mop head hydrangeas here. Check out these photos to see if you should prune your shrubs as new growth bloomers or as second year bloomers.

This is a Hydrangea arborescens, aka a smooth hydrangea. This one is Annebelle. If flowers on new growth so you can prune it in the early spring. Note that the more you cut it down, however, the newer and weaker the stems will be, so it’s more likely to flop when the heavy flowers form.

This is a Little Quickfire Hydrangea. It is a Hydrangea paniculata. These bloom on new growth, so they get pruned in early spring. Prune them by removing dead stems first, then looking for branches that are crossed and taking one away. Next remove any stems that are growing into the center of the plant. After that you can cut a bit “off the top” but like all shrubs, it’s folly to try and make it a lot shorter.

One of the most popular Hydrangea paniculata varieties on Cape Cod is the LimeLight. Prune it in the same way as described above for the Little Quickfire.

Lacecap hydrangeas form their flower buds the year before, so they should never get cut down much unless the canes have died over the winter. Prune in mid to late May, once you see which buds have made it through the winter and which ones have not. Remove any bare or dead cane or tips of canes, but leave everything else. If you try to make them smaller they won’t have many flowers.

Mophead hydrangeas also form their flowers in the year before. There is no time when you can cut them shorter without removing blooms. Prune in mid to late May by removing bare and dead canes only. If your plant is too tall for the location, move it!

This photo shows both types of hydrangeas. The blue flowers are Endless summer, which are pruned as second year bloomers even though they produce some flowers on new growth later in the summer. The largest flowering on Endless Summer is on second year growth so that's how they are treated. The white flowers in this photo are a Hydrangea arborescens. It is a new growth bloomer and gets pruned as such.

This photo shows both types of hydrangeas. The blue flowers are Endless summer, which are pruned as second year bloomers even though they produce some flowers on new growth later in the summer. The largest flowering on Endless Summer is on second year growth so that’s how they are treated. The white flowers in this photo are a Hydrangea arborescens. It is a new growth bloomer and gets pruned as such.

No matter which type of Hydrangea plants you have, know this: prune them to improve appearance, not control size. There is no way to make a large hydrangea small again. If your hydrangea has “gotten out of control” it isn’t really running amuck…it’s just done what plants are genetically programed to do: grow larger. If your shrub has grown over the windows or walkway, move it to another location and plant a variety of hydrangea that won’t get as large instead. Repeat after me: there is no way to make a large hydrangea small again. Give it up.

6 Comments

  1. Pat T. on April 24, 2015 at 8:21 am

    Thank you! I shared this with my neighbors in a new development with many types of these beautiful plants.

    • CLFornari on April 24, 2015 at 10:29 am

      Glad you found it useful, Pat!

  2. Alex Moore, MCLP on April 25, 2015 at 9:52 am

    Great blog! I shared it on our facebook page as this is a recurring questions with many of our customers and employees. I will be using this as a teaching tool to further educate all of our employees.

    • CLFornari on April 25, 2015 at 6:01 pm

      Thanks, Alex! So glad you found it useful. Now if it would just warm up a tad we’d all feel better about getting out there with the pruners…

  3. Emily W. on April 25, 2015 at 8:01 pm

    Great article and really helpful.
    I notice that you did not talk about pruning h. quercifolia. I have two “Alice” hydrangeas. I think that they are “supposed” to be pruned like second-year bloomers. But as they are still relatively bare of leaves, I see that mine are full of tangled stems, some of which are very thin. Any advice on pruning in the spring?

    • CLFornari on April 25, 2015 at 8:07 pm

      You are correct, Emily, that the oak leaf hydrangeas flower on “old growth” – but since they are not cane-growers like the mopheads and lacecaps, you’d prune them immediately after flowering. Any spring pruning would just be to remove deadwood and crossed/funky branches…kind of a spring “tune up” only!

Leave a Comment

You must be logged in to post a comment.

Subscribe To Our Newsletter

Sign up for our weekly email about sales and events.

Please enter a valid email address.
Something went wrong. Please check your entries and try again.