"Stop deadheading in the fall, when
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.
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.
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.
6. What to do if your hydrangeas have brown flowers? Clip those toasted blooms off, snipping just under the browned flower. Removing browned petals improves the look of the plant and for re-blooming varieties helps to promote the production of more flowers.
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.
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.
Cut the dead stumps down to their base to completely remove them. This will allow the new growth underneath to have a chance to succeed. Dead and old blooms need to be removed to make room for new buds to come through. Cut the flower head off right above the first few leaves to encourage blooms for the next summer.
New Wood Bloomers
These are the hydrangeas that set flower buds on current season wood (new wood). 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.
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.
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.
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.
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.
You need to protect your hydrangeas in the winter if your area gets freezing winter temperatures. Leaves, wood mulch and/or straw are good options to insulate your plants. Mound the mulch or leaves around your plants at least 12 inches high to protect the flower buds that will bloom early next year.
As the season progresses, the flowers deepen their pink finally turning red in the fall.
Hydrangeas don't look very nice in the winter. And they look even worse in the Spring! The old branches look dead at the end of winter (even though they're almost always just dormant); and they are unattractive for a while.