How to Prune Hydrangea Arborescens in the Late Fall: A Simple Guide for Georgina's Zone 5 Gardeners
Ah, the Hydrangea arborescens—also known as Smooth Hydrangea or, in some circles, “the plant that refuses to behave.” But, like all garden mischief-makers, these hardy shrubs just need a little TLC (that’s Tender Loving Cutbacks, in this case) to keep them from turning into a tangled mess. Late fall is the perfect time to give them a good pruning, especially if you’re in our Canadian growing zone 5, where timing can make all the difference between flourishing blooms and, well, disappointment.
Let’s get those pruners ready, and I’ll walk you through how to get your Hydrangea arborescens looking sleek and tidy for next year!
Why Prune Hydrangea Arborescens in Late Fall?
You’ve got two main reasons to prune this beauty in the late fall:
- Shape and Structure: Without pruning, your hydrangea might start to look like it’s auditioning for a role in a plant-based horror movie. Regular pruning helps maintain its natural, rounded shape.
- Bigger Blooms: Hydrangea arborescens blooms on new wood (aka new growth), so pruning it back encourages bigger and more abundant flowers next summer. If you skip this step, the flowers can start getting smaller and less showy.
When to Prune Hydrangea Arborescens in Zone 5
In Georgina, late fall (after the leaves drop but before the ground freezes) is an ideal time to prune. You want the plant to be fully dormant, meaning the plant has gone to sleep for the winter, and you’re not cutting into anything actively growing.
Prune too early, and you risk encouraging new growth that will just get zapped by frost. Prune too late, and you’ll be working in freezing temperatures, which is nobody’s idea of gardening fun.
Tools You'll Need
- Sharp bypass pruners: Dull pruners = crushed stems = unhappy hydrangea.
- Gloves: Because why risk hand scratches when you don’t have to? - Rake: You’ll want to clean up fallen leaves and debris before you get started.
- Mulch (optional): A nice layer of mulch post-pruning can protect your plant’s roots over the winter.
Step-by-Step Guide to Pruning Hydrangea Arborescens
1. Clean Up the Area
Start by raking away any fallen leaves or debris around the base of the plant. You don’t want to trip over last summer’s leftovers while you’re wielding sharp tools. Plus, it reduces the risk of disease spreading from rotting plant material.
2. Cut Back the Stems
Now for the fun part: pruning! Hydrangea arborescens can be pruned back to about 8 to 12 inches from the ground. If that feels too drastic, don’t worry—this variety of hydrangea is resilient and will bounce back with gusto. Here’s how to cut it back:
- Remove dead or damaged stems first. These are just freeloaders at this point, so snip them off right at the base.
- Then, cut back the remaining stems, making your cuts just above a pair of healthy buds. Aim to leave a framework of about 5 to 10 strong stems so the plant doesn’t get too congested next season.
3. Thin Out Crowded Stems
If your hydrangea is starting to look like it could form its own hedgerow, you’ll want to thin out some of the older, woodier stems. Remove about a third of the oldest stems right at the base to allow for better air circulation and more room for new growth.
4. Shape the Plant
Once you’ve thinned it out, step back and take a look. Trim any errant branches that are sticking out at awkward angles. Remember, we’re going for that lovely rounded shape, not a shrub that looks like it’s reaching for the neighbours’ yard.
5. Clean Up Again
After all the cutting and trimming, make sure you clean up the area. This is especially important if any of the stems you pruned had signs of disease or damage. You don’t want to leave any remnants behind that could invite pests or diseases.
Extra Care: Mulching for Winter Protection
While hydrangea arborescens is pretty hardy, a little mulch love doesn’t hurt. A 2-3 inch layer of mulch around the base of the plant helps insulate the roots during the freezing winter months. This is particularly helpful in Keswick, where winters can be tough on even the hardiest of plants.
What NOT to Do
- Don’t prune too high. If you leave too much stem, your blooms will be smaller next year.
- Don’t prune in the spring. You might accidentally cut off the buds that are just starting to form, which means no flowers. And no one wants that.
- Don’t leave diseased stems or leaves. If you spot any powdery mildew or rot, toss those clippings in the trash—not the compost pile.
Pruned and Ready for Spring
By following these simple steps, your Hydrangea arborescens will be ready to rest through the winter and come back stronger, bigger, and bloomier (yes, that’s a word now) next year.
So, there you have it, grab those pruners, embrace the crisp fall air, and give your hydrangeas the cutback they deserve! Now, sit back, relax, and look forward to a summer filled with lush, giant blooms. After all, isn’t that the whole point?
Happy gardening!
Shannon, the Garden Girl
Shannon, the Garden Girl, shows how to prune Annabelle hydrangeas which will benefit them next season. They will come back just as big, if not bigger and will have more prolific blooms. Learn her easy pruning technique that you can use on any Hydrangea arborescens varieties.