Hydrangeas that bloom on new wood require pruning in late winter or early spring. Prune to shape, cutting back to about two feet. The pruning promotes new, sturdy growth, which provides the blooms next season.
"When to prune these woody-stemmed hydrangeas is not as critical as [with old wood] varieties, as long as you avoid pruning when the flower buds are opening," says Becker. Trim in early spring, before the flowers begin to bud, or after the plant has finished flowering.
But if you do choose to prune one, remember this: Time it based on whether the type of hydrangea you have blooms on old wood or on new wood. If it blooms on old wood (stems from the summer before the current one), its buds are being formed, and if you wait too late you may cut them off, meaning no flowers next spring.
Bottom-line: Panicle-type hydrangeas should be pruned in late winter or early spring. While they could be pruned in fall, we highly advise waiting until late winter/early spring to reduce risk of injury.
While some plants bloom on new growth, others primarily set flower buds on old wood. Regardless, it is best to wait to prune all hydrangeas until spring. In the fall, hydrangeas (and all trees and shrubs) are in the process of going dormant. They do not produce very much new growth until the following spring.
Prune fall blooming hydrangeas, or old wood bloomers, after they bloom in the summer. If you prune old wooded hydrangeas in fall, you are cutting off next seasons blooms. Summer blooming hydrangeas, or those that bloom on new wood, are pruned in the fall, after they stop blooming.
Wrap with winter protection.
During the winter, make a DIY A-frame wire cage out of burlap and chicken wire to protect your hydrangea plant. This cage will protect it from winter winds, heavy snowfall, and cold temperatures.
In late winter or early spring, these shrubs can be cut all the way back to the ground. Smooth hydrangeas will produce much larger blooms if pruned hard like this each year, but many gardeners opt for smaller blooms on sturdier stems.
Prune about a third of the stems a little harder down the stem to get good foliage and big flowers in summer. It might look like a very severe prune, but in actual fact, I've only taken off about two-thirds of the plant. I've left another third to grow on.
Smooth Hydrangeas should be pruned in late winter/early spring, and they can be cut down to the ground if you wish. Pruning will encourage new growth in these varieties and can help increase flowers.
When to prune hydrangeas. Most pruning is carried out in late winter or early spring. However, the climbing hydrangea is pruned after flowering in summer.
To prepare hydrangeas for winter in colder areas, add a thick layer of mulch around the base of the plants to protect the crown and roots from freezing temperatures.
When is Late Winter? Late winter is 4 to 6 weeks before spring thaw begins. This could be any time in January to May, depending on your climate.
Without going through the deadheading process, hydrangeas will not produce as many flowers and the few produced may not grow as big to their full potential.
Hydrangeas that bloom on new wood require pruning in late winter or early spring. Prune to shape, cutting back to about two feet. The pruning promotes new, sturdy growth, which provides the blooms next season.
With their vibrant, plump blooms, hydrangeas offer a striking display in the warm weather - but what do they look like in the winter? As the delicate petals fade in the colder months, bright hydrangeas can quickly appear dry and brown - requiring targeted care to get them flowering again in April.
Some varieties, like smooth hydrangea (“Annabelle”) and panicle, or PG hydrangea, are very cold-hardy and bloom on new wood. If these are the species in your garden, you don't have to worry about winter kill on hydrangea. They don't need protection unless the temperature dips below negative 30 degrees F.
New Wood Bloomers
It is easy to grow these hydrangeas because they bloom every year regardless of how they are cared for or treated. They can be pruned to the ground in the fall and they will emerge in the spring with bountiful blooms.
Mophead hydrangeas look lovely in the fall when their blue, purple and pink flowers contrast with the fall foliage. Brown flowers can be snipped off if they annoy you, but you don't have to remove them. Look for flowers like this to dry or for making Hydrangea Wreaths.
Many customers ask why their hydrangeas aren't blooming. The primary reasons hydrangeas don't bloom are incorrect pruning, bud damage due to winter and/or early spring weather, location and too much fertilizer.
Prune back stems to just above a fat bud — called a heading cut — in fall, late winter, or spring. These plants have conical-shaped flower heads that provide nice winter interest in your landscape, so wait to prune these until late winter or spring.