No, You do Not Have to Prune Your Hydrangeas
We're often asked, "when do I prune my hydrangeas" as if it's a must-do situation, like "when should I put my Jack-o'-Lantern on the compost heap? (Scroll to the bottom for a tiny rant about Christmas pumpkins.)
There's been loud gardening static regarding there being a right time and a wrong time to prune, so it's pretty thrilling that most recent hydrangea enthusiasts understand there are a lot of flower buds at stake if pruning is done at the wrong time.
Read our pruning calendar by hydrangea species: When to Prune Hydrangeas
However, seems people are thinking they absolutely have-to, must-to, got-to prune their hydrangeas. Folks are under the impression that the first rule of being a good hydrangea parent is to constantly be pruning pruning pruning. It's interesting that we've never once been asked, "Do I have to prune my hydrangea?"
Dear hydrangea pilgrim, you're freed! You don't have to prune your hydrangeas. There are a few circumstances when you'd want to ask yourself, "is it necessary to prune my hydrangeas?" We'll discuss them right now.
A) The hydrangea bush is too big.
Hydrangea paniculata, panicle hydrangea, is sometimes called "tree hydrangea" which tells you something about potential size - most cultivars get over 10' tall. That's taller than most one-story roof lines.
Hydrangea macrophylla, bigleaf hydrangea, can get HUGE over time. I've seen old ones that are easily 6-7' tall. I didn't have a tape measure with me, but it was taller than my 6' friend.
Same for Hydrangea quercifolia, oakleaf hydrangea - this shrub can become a massive bulk of foliage in your garden and look like it will muscle a wall out of the way (don't worry, it won't).
There are two solutions for too-big hydrangeas:
- Choose the right-sized hydrangea in the first place. If you have a 4' wide nook and don't want a hydrangea to get taller than 4', choose one that stays smaller. There are many smaller options for panicle, bigleaf, and oakleaf hydrangeas. Do a little research first and you won't have to prune as hard later. We'll write about smaller hydrangeas in a post coming up soon.
- Prune every couple of years to reduce size. Arborists have a technique called a reduction cut that is the science and art of making a branch shorter in a healthy and aesthetic way. Make reduction cuts as needed and/or prune out the largest, tallest branches from the base of the plant.
B) The hydrangea isn't obnoxiously large, but it's co-mingling a little too much with its neighbors.
Besides the hosta, the picture at the top shows two bigleaf hydrangeas crammed together in a way I think looks fantastic this year. However, next year they may be too crowded and take up each other's space. Especially that blue one may overshadow the blurple one (blurple is the zaniest word and it means a bigleaf hydrangea with two different flower colors on the same plant).
After the blue one flowers this year, I would thoughtfully and patiently make some reduction cuts to prune out the largest branches so it doesn't overshadow the blurple one over the next several years.
C) The plant has thrown out a wild rangy branch.
Again, take a look at the blurple hydrangea in this pic. See that taller branch in the front? It bothers me. The plant isn't balanced and it will likely be more unbalanced next year. If that branch had flowers on it, I might be more accepting of it this year, but it doesn't have flowers. I would unholster my pruners and . . . CLIP. Gone.
This is pure fantasy pruning because the picture was taken on a garden tour and I would have been kicked out. If they'd have let me, I would have done one of two things:
i) Pruned the branch 1/3 to 1/2 way down the stem so the buds there would grow and that area would have more branches.
ii) Rummaged around in the shrub to see if maybe that entire branch should be cut off from the base. If there was a cluster of new branches starting to grow down there, I would have cut off the entire branch to give the new ones more room.
D) You want to remove the hydrangea flowers.
Removing hydrangea flowers is called deadheading. Deadheading is technically pruning because we have pruners in our hands when we work on deadheading a plant. We've gone on and on about deadheading hydrangeas under a separate bog post.
Please read: How to Deadhead Hydrangeas.
Did we miss anything? Let us know in the comments section below.
Happy Pruning (if necessary),
Hillary & Mike
When should I put my Jack-o'-Lantern on the compost heap?
A pumpkin should be composted by the end of October, but, if you're somehow cute and stylish about it, you can get away with having it on display until Thanksgiving. Certainly by Christmas, the pumpkin should not remain on the stoop.