Become a Member
Facebook
Twitter
YouTube
Instagram
Pinterest
  • New Plants
    • New Plants Search
    • Green Thumb Award Winners
  • Year Of Plants
    • Year of the Amaryllis
      • Amaryllis Pictures
    • Year of the Broccoli
      • Broccoli Pictures
    • Year of the Celosia
      • Celosia Pictures
    • Year of the Orchid
      • Orchid Pictures
    • Year of the Rudbeckia
      • Rudbeckia Pictures
    • Year of the Spirea
      • Spirea Pictures
    • 2022 Year Of Plants
      • Year of the Gladiolus
        • Gladiolus Pictures
      • Year of the Lilac
        • Lilac Pictures
      • Year of the Peperomia
        • Peperomia Pictures
      • Year of the Phlox
        • Phlox Pictures
      • Year of the Salad Greens
        • Salad Greens Pictures
      • Year of the Verbena
        • Verbena Pictures
    • 2021 Year Of Plants
      • Year of the Hardy Hibiscus
        • Hardy Hibiscus Pictures
      • Year of the Garden Bean
        • Garden Bean Pictures
      • Year of the Hyacinth
        • Hyacinth Pictures
      • Year of the Monarda
        • Monarda Pictures
      • Year of the Sunflower
        • Sunflower Pictures
        • #YearoftheSunflower Video Contest Winners
    • 2020 Year Of Plants
      • Year of the Lavender
        • Lavender Pictures
      • Year of the Lantana
        • Lantana Pictures
      • Year of the Hydrangea
        • Hydrangea Pictures
      • Year of the Iris
        • Iris Pictures
      • Year of the Corn
        • Corn Pictures
    • 2019 Year Of Plants
      • Year of the Snapdragon
        • Snapdragon Pictures
      • Year of the Dahlia
        • Dahlia pictures
      • Year of the Pumpkin
        • Pumpkin Pictures
      • Year of the Salvia nemorosa
        • Salvia nemorosa pictures
    • 2018 Year Of Plants
      • Year of the Coreopsis
        • Coreopsis Pictures
      • Year of the Tulip
        • Tulip Pictures
      • Year of the Calibrachoa
        • Calibrachoa Pictures
      • Year of the Beet
        • Beet Pictures
    • 2017 Year Of Plants
      • Year of the Daffodil
        • Daffodil Pictures
      • Year of the Brassica
        • Brassica Pictures
      • Year of the Rose
        • Rose Pictures
      • Year of the Pansy
        • Pansy Pictures
  • Combo Ideas
  • Inspiration
    • NGB Blog
    • FAQs
    • Newsletter
    • Pinterest
    • Promote Gardening
    • #YearoftheSunflower Video Contest Winners
    • Snapdragon Video Winners
  • Education
    • Member Blogs
    • Books
    • Online Courses
    • Podcasts
    • Videos
    • Webinars
  • Products
    • Garden Books
    • Garden Décor
    • Garden Tools
    • Green Thumb Award Winners
  • Shop Members
    • United States
    • Canada
  • Garden Grant
    • Grant Application
    • Therapeutic Grant Program
  • Contact
Beware of the Hydrangea Danger Zone when pruning your Hydrangeas - National Garden Bureau

Hydrangea Danger Zone

How-to, Plant Care & MaintenanceMarch 18, 2021gail

Oh, no! Something else to worry about? Yes, I’m afraid there is.

What is the Hydrangea Danger Zone™?

Right now you and all other gardeners who grow hydrangeas could be in the Hydrangea Danger Zone. It’s that time between the fall when your “old wood” hydrangeas set their flower buds, and the coming spring when those buds emerge. That is if they have made it through the winter.
But what makes it so dangerous, you may ask. We, the gardeners! We want to get outside at the first sign of warm weather and start pruning our plants. Therein lies the problem. If you cut your old wood hydrangeas now before you see those new buds, you could actually unwittingly remove those buds. Then all you will have is a nice green bush – Mon dieu!

The Key is to Know Which Hydrangeas Flower on Old Wood

So you need to figure out which of your hydrangeas flower on old wood. Those are the stems that have the flower buds you want to protect from pruning cuts. I can help you with that.
Oakleaf Hydrangeas flower on old wood so do not prune in the spring - National Garden Bureau
If your flowers are cone-shaped and change color from white or cream to shades of pink and rose, and the leaves look like an oak leaf, that’s an oak leaf hydrangea (quercifolia). Oakleaf hydrangeas always flower on old wood.
Climbing Hydrangea blooms on old wood - National Garden Bureau
If you’re lucky enough to have a hydrangea that’s a vine, that’s a climbing hydrangea (anomala petiolaris)
which also flowers on old wood.
If your flowers are round and blue, that’s a big leaf hydrangea and old wood - National Garden Bureau
If your flowers are round and blue, that’s a big leaf hydrangea (macrophylla), an old wood flowering plant or a mountain hydrangea (serrata). Newer cultivars like Endless Summer bigleaf hydrangeas and Tuff Stuff mountain hydrangea are remontant, meaning they bloom on old and new wood.
Lacecap Flower Hydrangea - Old wood - National Garden Bureau
Those flowers can also be somewhat flat and even lacey-looking. This lacecap flower can be on your big leaf (macrophylla) or your mountain hydrangeas (serrata). Lacecap flowers can come on plants that flower on old wood.
Bigleaf Hydrangea with white flowers - National Garden Bureau
But what if you have a plant with round flowers that are white and don’t change color? That’s also a big leaf (macrophylla) hydrangea.
Hydrangea Annabelle
If it doesn’t change to blue and stays some shade of cream or pink, it could be a woodland/smooth hydrangea (arborescens) like ‘Annabelle.’ The foliage will confirm which it is so check it out to be sure.

Exactly What You CAN Cut Now

Any of your purely new wood bloomers can be cut and trimmed now. That means you can take care of your panicle and woodland plants. No worries since their flowers this year will come from the growth they put on in the spring. In fact, pruning cuts can stimulate them to produce more flowers.

What Plants Should I Leave Alone?

Leave your oakleaf and climbing alone unless you have dead, diseased, or damaged wood that needs to be removed.
Hydrangea's tiny buds are often called broccoli - National Garden Bureau
Try your best to leave your big leaf and mountain hydrangeas alone as well. Those old wood flowers will start to show their buds soon. The best thing you can do is wait for your plant to break dormancy. Then inspect it for those tiny little buds called “broccoli”.

If your plant has outgrown its allotted space and you don’t care about losing flowers, then cut away. I would personally prefer to first get the flowers this season and then cut it back before August 1.

Do I Treat Rebloomers Differently? 

We already know that reblooming big leaf hydrangeas can flower on new wood, but don’t think that rebloomers flower ONLY on new wood. Au contraire, rebloomers have both old and new wood genetics. And those old wood buds are waiting to come out and play. They, therefore, need to be protected from premature pruning.
If it’s a rebloomer, it’s even safer to wait until you have passed your last frost-free date. That’s because
rebloomers can give you a second season of flowers as long as those sleeping buds haven’t awakened. Sometimes when we cut before that last frost-free date, the reblooming buds start swelling as spring temps warm-up. Then they get zapped by a late-season weather event like snow or ice. I speak from experience.

The Wisdom of Doing Nothing

You are left with a couple of options for big leaf and mountain hydrangeas: do nothing which is fine and more than acceptable. Or you can wait to see those buds and do everything you can to protect them if ol’ man winter comes back one more time.

If I Can’t Prune, Exactly What Else Can I Do?

Scratch that gardening itch by cleaning up your gardening tools and sharpening your pruners. Not only will you feel holy but you’ll be ready for the right time when you can confidently cut your old wood plants safely.

Now, do you see why I call it the Hydrangea Danger Zone?

Written By: Lorraine Ballato
Author of: Success With Hydrangeas: A Gardener’s Guide

Learn more about Hydrangeas at…

  • Year of the Hydrangea
  • 4 Hydrangea Myths Busted
  • The Best Time to Prune Your Hydrange
  • Blooming Hydrangeas Guaranteed!
  • Preparing Your Hydrangeas for Winter
  • Hydrangea Checkup Time
  • Shrubs for Cutting Gardens: Roses, Hydrangeas, and Other Long-Lasting Flowers

“This post on Hydrangea Danger Zone is provided as an educational/inspirational service of the National Garden Bureau and our members. Please credit and link to National Garden Bureau and author member when using all or parts of this article.”

Pin It for Later…

Beware of the Hydrangea Danger Zone - The Key is to Know Which Hydrangeas Flower on Old Wood - National Garden Bureau
Previous post How to Grow Spring Blooming Hellebore Flowers Next post Companions for NGB’s Plants of the Year

3 comments. Leave new

Catherine Gervase
May 22, 2021 3:16 pm

We moved into our house in the Fall about 30 years ago. At that time, we were told that a massive bush in the back was a beautiful. We seems to get the ‘broccoli’ every year but no flowers. Not knowing anything about them, I’ve pruned it at various times. I’ve also left it unpruned for a couple years in a row. Nothing seems to work. What might I be doing wrong? At the time we moved in, the bush was in the shadow of a 40′ weeping willow which we had to remove. Now the bush gets sun pretty much all day. Could that be the reason?

Reply
National Garden Bureau
May 24, 2021 5:41 pm

We asked Lorraine Ballato, author of this article, and she said…
First of all, you can be sure your plant was a hydrangea that flowers on old wood. That’s the growth it put on last season. So that means no pruning at all (which you have already practiced), or pruning only after you see “broccoli.”

If you are getting “broccoli,” you should be getting flowers from those buds. The only thing I can think of is water (excess or stress) might be robbing your plant of the energy it needs to turn those buds into flowers. The second possibility is soil fertility. Somehow your plant just doesn’t get enough to make those buds into a flower.

That being said, 2 things you can do: first, do a soil test and see what you are working with. If you need to fertilize/amend, use a granular slow-release product made for shrubs. Rose food is ideal. Follow the directions on the label.

The second action is a little more involved. Stick your finger in the ground around the base of your plant, going outward to the ground below where the stems extend (that is called the “drip line”). If it is dry at your second knuckle, your plant needs water. Test and retest regularly to see how often you get that result. You may have to add more compost and mulch to help your plant retain moisture better. You mentioned your plant gets sun pretty much all day. So if you are in the southern states, that sun may be frying your plant and causing water stress.

You could also move your plant to a place where it gets only a half-day of sun and give it some relief. Or you can plant something close enough to provide shade without creating root competition. I put in a ‘Bloomerang’ Lilac to provide that necessary afternoon shade. The lilac grows quickly, stays small enough to easily manage, repeat blooms, and protects my hydrangea from the afternoon sun. There are lots of plants that can do this for you.

If that second knuckle is wet and you have had no rain, the plant might be getting TOO MUCH water. Hydrangeas love water to the extent that they make leaves instead of flowers when they get a lot of it. Test and retest regularly to see how often you get this result. Then you may have to back off your irrigation if you have it, or amend your soil to be less water retentive, or move the plant to a site that doesn’t drain so quickly.

In my best-selling Success With Hydrangeas book, I discuss the many ways you can grow this magnificent shrub. You might also get some pointers from my hydrangea blog.

Reply
Sonia Day
March 23, 2021 12:21 pm

Very good article, thank you. Well explained, good photos, easy to follow

Reply

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Recipe Rating




Follow Blog via Email

Sign-Up to receive notifications of our new posts.

Search

Topics

  • DIY Crafts & Gifts
  • Flower Shows and Festivals
  • Garden Grant Recipients
  • Gardening as Therapy
  • Gardening Books
  • How-to
  • Indoor Gardening
  • Kid's Gardening
  • Planning and Design
    • Backyard Habitat
    • Container Gardening
    • Garden Planning & Design
    • Perennials
    • Plants for Shade
  • Plant Care
    • Pests and Diseases
    • Plant Care & Maintenance
    • Soil, Compost and Mulch
    • Winter Gardening
  • Planting
    • Flower Gardening
    • Foodscaping
    • Herbs
    • Planting Tips
    • Seeds and Seed Starting
    • Vegetables
  • Pollinator Gardening
  • Recipes

Archives

  • March 2023
  • February 2023
  • January 2023
  • October 2022
  • September 2022
  • August 2022
  • July 2022
  • June 2022
  • May 2022
  • April 2022
  • March 2022
  • February 2022
  • January 2022
  • December 2021
  • November 2021
  • October 2021
  • September 2021
  • August 2021
  • July 2021
  • June 2021
  • May 2021
  • April 2021
  • March 2021
  • February 2021
  • January 2021
  • December 2020
  • November 2020
  • October 2020
  • September 2020
  • August 2020
  • July 2020
  • June 2020
  • May 2020
  • April 2020
  • March 2020
  • February 2020
  • January 2020
  • December 2019
  • November 2019
  • October 2019
  • September 2019
  • August 2019
  • July 2019
  • June 2019
  • May 2019
  • April 2019
  • March 2019
  • February 2019
  • January 2019
  • December 2018
  • November 2018
  • October 2018
  • September 2018
  • August 2018
  • July 2018
  • June 2018
  • May 2018
  • April 2018
  • March 2018
  • February 2018
  • January 2018
  • October 2017
  • September 2017
  • August 2017
  • June 2017
  • May 2017
  • April 2017
  • February 2017

Contact

National Garden Bureau
5201 Walnut Ave., Suite 3
Downers Grove, IL 60515
Phone: 630-963-0770
Email

Quick Links

New Plants
2022 Year Of Plants
Inspiration
Shop Our Members
National Promotions
Garden Grant
AAS Winners
Video Contest Winners

About NGB

Who We Are
Become a Member
Member Directory
Member Photo Libraries
NGB in the News

Newsletter Sign-Up

Sign-Up for our Newsletter Here

Copyright © 2023 National Garden Bureau. All rights reserved.
Hydrangea Expert Ebook