In colder climates, wrap or completely cover marginally hardy hydrangeas. This is especially important for those that bloom on old wood, such as mop head/big leaf hydrangeas (
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.
4. No need to prune. If you trim your plants in fall or winter, you may mistakenly remove flower buds for the following year on bigleaf and oakleaf hydrangeas. Leaving the old flower heads on the plants will also add some interest to the winter landscape.
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.
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.
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.
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.
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.
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.
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.
Big Leaf Hydrangeas, Hydrangea maculata, do not tolerate frosts well and should be covered to prevent leaf damage and flower loss.
Most common hydrangeas prefer a partial sun location - ideally receiving sun in the morning hours and shade in the afternoon. The reblooming Endless Summer® Hydrangea series prefers part shade.
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 prune them at the wrong time, you could risk cutting off all the flower buds and ending up with no blooms that year.
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.
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. Hydrangea varieties can be of the type that blooms on old wood, new wood or both. Old wood is the current year's growth and new wood is next year's (spring) growth.
During the winter months, most of the blooms fall from the plant and whatever is left often turns dry and brown. The cold winter weather can leave the remaining foliage and buds of hydrangeas dead and damaged - but what's the most likely cause?
Regardless of the type of hydrangeas you're growing—and whether it blooms on old or new wood—the cutting process is the same. Start by using clean, sharp shears, then make your cut. "Cut stems above a node, and include at least two leaf groups on the cut stem," says Godshalk.
It's best to start adding coffee grounds to the soil months before the blooming season begins, ideally in the late fall. You can repeat the process with your typical fertilizing schedule. With a little caffeine and a lot of patience, your hydrangeas should reward your efforts come spring with the boldest blue globes.