When to Deadhead Hydrangeas. You should deadhead throughout the blooming season to keep your hydrangeas looking their beast and encourage new flower growth. However, stop deadheading hydrangea shrubs in mid to late fall, leaving any spent blooms in place.
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.
"Bigleaf hydrangeas, such as endless summer, should be deadheaded when the first set of flowers sprout from last year's growth in the spring," says Meyers. This eliminates the faded flowers before the next flush appears.
Blooming hydrangeas are one of the most elegant and beautiful highlights in any garden. Starting in mid summer and continuing into September, Hydrangea paniculatas take center stage. With their fresh foliage and large cone shaped flowers, they add a dramatic accent to any garden border or planting bed.
You'll find hydrangeas growing in hardiness Zones 3 to 7 as perennials. With flowers starting in spring and often last throughout summer into early fall, hydrangea flowers can be the foundation plant of your landscape.
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.
"Stop deadheading in the fall, when bigleaf hydrangeas produce their last flush of flowers, to enjoy the dried blooms throughout the winter," she says. "These can be removed to help produce healthy buds in the 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.
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.
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.
If you prune them at the wrong time, you could risk cutting off all the flower buds and ending up with no blooms that year.
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.
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.
Provided that you give your reblooming Hydrangeas the proper care, you may have blooms that last until the first frost. Reblooming varieties extend the season through the fall because a second set of buds form on the new wood creating a second bloom.
Fall Bloomers
"Re-blooming varieties of Hydrangea macrophylla may produce some blooms into the fall," he adds. "Varieties like 'Seaside Serenade Newport' have flowers that can last for a couple of months—so they can continue to add beauty in autumn with their summer blossoms."
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.
As to when hydrangeas bloom, the simple answer is that a usually a hydrangea flowers from mid-spring through the late summer or early fall.
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.
According to Hirvela, your hydrangea is done blooming when the color of the flowers has faded in a non-appealing way. "There are a few varieties that will continue to push out new buds through late summer and autumn," she says.