"Re-blooming varieties of
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.
Some introductions such as the Forever and Ever series or the well known Endless Summer family bloom both on old wood and new wood. The spring flowers occur on the prior year's old wood, while the fall flowers occur on the plant's current-season new-wood growth.
Quick Fire® Hardy Hydrangea: This Paniculata actually starts blooming a month earlier than her brethren…but will continue to bloom into the fall. Her blooms start out white, but turn to dark pink as time marches on. She'll grow to be about 6'-8' tall and wide.
So, while fresh flowers have a particular type of loveliness, in some ways hydrangeas improve when Autumn throws a restraining hand on the foliage, adding pink, purple and yellow where there was only green. The flowers both brighten and fade, losing some of their stiffness and gaining a more soulful air.
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.
If you like the look of dried flower heads in your garden in the wintertime, leave them on and prune them in spring. If you live someplace where there is a heavy snow load or if you prefer a tidier look in winter, prune them in late fall to early winter.
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.
Reblooming Hydrangea Varieties
Plant a variety that blooms off both old and new wood for successive flowering. They are called remontant, which means reblooming. One of the first introduced was 'Endless Summer,' a blue mophead variety, but there are many others now available.
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. I recommend leaving the dry, tan flower heads on the plant to provide some winter interest in your landscape, so I wait to prune these until late winter or spring.
If you don't prune hydrangeas then they can eventually resemble a tangled mass of woody stems, and the flowers will become smaller and less showy.
"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."
Unlike other flowers, deadheading hydrangeas will not make them bloom again. Regular hydrangeas bloom once per season, while reblooming varieties produce a second set of flowers later in the season on new stems.
They are not winter flowers. Hydrangeas primarily bloom during the summer months. A few varieties of Hydrangeas may bloom in spring or late summer, depending on the climate. Although Hydrangeas do not bloom in winter, you still want to care for them over the winter months, especially in cold climates.
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.
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.
The safest practice is to clip back individual flowers right after they bloom and not to prune after August 1st. If you need to do a reshaping pruning, typically that is done by cutting back just a third of the branches at a time over a period of three years, so that the plant stays strong and flowering.
Brown, tan, yellowish or black spots on hydrangea leaves may be anthracnose. You can also identify it by cankers that form on stems and branches. Anthracnose can be fatal to hydrangeas, so prune out dead or diseased plant parts and destroy them.
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.