When to prune? Prune these hydrangeas only after bloom in the summer and not in the fall. Old wood hydrangeas start developing their bloom buds for next year in August and September. If you don't prune your hydrangeas real soon, then it is better to wait until next year.
To reduce the size of a hydrangea that blooms on new wood, cut off about one-third of each stem in late fall or early spring before it begins to leaf out. If your hydrangea blooms on old wood, prune right after it has bloomed when the flowers are fading.
But when to prune them? 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.
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.
Hydrangeas that bloom on new wood can be safely pruned in late fall once the plants have gone dormant or in early spring. Next year's flower buds won't be formed until late spring the same year they bloom, so there is no risk of removing the buds if you prune in fall or spring.
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.
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.
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.
The best time to deadhead is when the first set of blooms on your hydrangeas begin to turn brown and dry. Cut the stem below the flower head and just above the first set of leaves. For reblooming types, you can deadhead again when this second set begins to fade, but only through mid-August or so.
Enormous flowers in white, pink or blue that change colour to autumnal shades of red, brown or green. Obviously we're talking about the hydrangea. This flower fits perfectly with September, the month in which summer cautiously gives way to autumn.
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.
However, stop deadheading hydrangea shrubs in mid to late fall, leaving any spent blooms in place. This not only provides winter interest, but also ensures you don't remove the buds that will become flowers next spring.
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.
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.
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.
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.
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.