We love hydrangeas! Who doesn’t? They’re always enchanting, but sometimes they can also be a little mystifying. We get a lot of questions about how and when to prune them. To help you out, here are the basics.
First, pruning depends on the type of hydrangea, and there are three types that we grow here in zone 4.
Smooth hydrangea – (Hydrangea aborecsens)
These produce large, round white blooms and include the ever-popular Annabelle.
This variety blooms only on new wood. Prune back to 1-2 feet above the ground or to the first pair of buds just above the ground in late winter or early spring, either before they break dormancy or just as the buds begin to form. This will encourage new growth and lead to more flowers. It will also produce sturdier stems and a fuller growth habit. If you choose not to prune back, just remove any dead or diseased stems.
Panicle hydrangeas (Hydrangea paniculata)
Panicle hydrangeas produce cone-shaped flowers and bloom on new wood. This category includes a large variety of hydrangeas.
A few common panicles
- Vanilla Strawberry
- Quick Fire
- Strawberry Sundae
- Pinky Winky
Cut panicle hydrangeas back in spring, before they begin to leaf out. They can be cut back close to the ground, but to encourage taller plants, cut back about 30-50% of the length of each stem. Start on the outside and cut back stem by stem. Prune each stem at a 45-degree angle and try to maintain a rounded shape. Close to rounded is good enough – they’ll be beautiful without being perfectly manicured.
A well-established shrub (one that is a few years old) will benefit from removing the oldest wood down to the ground, about 1/3 each year.
Tree forms are always panicle hydrangeas. If suckers come up from the ground around the trunk, remove them promptly. Cut back branches to 2-3 nodes in early spring. The nodes will become flower shoots later in summer. Do not prune in summer since this will affect flowering, but it’s OK to prune branches damaged by wind or storms.
Here’s Megan with a demonstration on how to prune panicle hydrangeas.
Bigleaf Hydrangea (Hydrangea macrophylla)
These are the Endless Summer variety that produce big pink or blue rounded blooms. Luckily, they bloom on both old and new wood and never really need much pruning. Just wait until the plant shows leaves and cut back only dead or crazy-looking branches.
In summer, after the first set of blooms finishes, trim back just behind spent flowers and a new set of blooms will show up a little later. We had great success last year by pruning Endless Summers back mid-summer when they started to look leggy and unkempt and were slightly storm damaged. They produced a second bloom on a much nicer-looking plant with a more rounded and contained growth habit.
If you find that you have waited too long to prune and your shrub has already leafed out, don’t worry. Generally, hydrangeas don’t really need to be pruned, other than dead or diseased branches. Doing so just helps maintain a nice shape and encourages blooms, but the shrub will be fine and you can just prune next year instead. Mark your calendars now!
If you prune your hydrangea back at the wrong time you may see fewer of no blooms for a season, but the shrub will recover and produce blooms the next year. First identify which kind of hydrangea you have, then plan for pruning.
A terribly overgrown shrub can be rejuvenated by cutting back all the stems to a foot or two above the ground. This will allow the shrub to produce new growth and will help restore it to it’s initial growth habit and attractive shape.