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.
Hydrangea paniculata and Hydrangea aborescens produce flowers on new wood, which means that you can cut them back harder without losing this year's flowers. Pruning is not essential, but left unpruned the plant will get taller, with most of the flowers at the top.
Once the shrub is established and has a couple of growing seasons under its belt, prune these hydrangeas in the spring down to the ground, or not at all if you want a larger shrub. Flower buds will grow on this season's growth or new wood.
A bigleaf hydrangea can be pruned back by one-third of its total mass, but harsher pruning will weaken the shrub and cause it to languish for a season or two.
So, in October or November, simply cut all branches back to about 6 to 8 inches (15 to 20 cm) from the top of the trunk. Once you've gotten your hydrangea tree back into a more winter-resistant shape, start pruning early in the spring rather than the fall.
After a day or so of being cut, the blooms begin to wilt. About three days later, they are completely done. But guess what I just learned (from an instagram conversation)? Hydrangeas take in water from their PETALS!
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.
Old Wood Bloomers
Hydrangeas that bloom on old wood do not need pruning and are better off for it.
When to prune hydrangeas. Most pruning is carried out in late winter or early spring. However, the climbing hydrangea is pruned after flowering in summer.
Good thing is, hydrangeas are hardy plants and as much as the damage might seem serious, they are bound to recover under good care. Start by pruning back any seriously frost-damaged growth using a sterilized and sharp pruning shear to promote new and healthy growth in the summer (avoid cutting back into the wood).
As soon as hydrangeas are cut, the stems should immediately be put into tepid water. And adding a little bit of flower food to it would be a great idea too. Use a sharp knife or clippers to cut each stem on a diagonal and submerge! Cut hydrangeas in the morning and choose only the most mature blooms.
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.
So these shrubs should be pruned immediately after their flowers fade. Conversely, if the shrub flowers on new wood (stems developed during the current season), its buds are set within the season, so the shrub should be pruned in early spring before that new growth emerges.
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.
Removing spent flowers will ensure your hydrangeas produce healthier, more bountiful blooms later on.
It is suggested that Hydrangea wilt so soon after being cut because their stems contain a sticky substance that clogs the stems preventing moisture reaching the top of the stem to the head. Top Tip - Cut 10 cm off the stem and place in boiling water and leave for 24 hours.
First, add a 1/4 cup of sugar to the room temperature water in the vase. The sugar helps feed the stems and increases the life of the cut flowers.
Plants grow toward their light source. Without sufficient sunlight, Hydrangeas will reach for the sun, resulting in the top areas of the plant becoming denser than the bottom. Hydrangeas grow best when they get full sun in the morning and filtered light throughout the day.
Some gardeners report success in turning their hydrangeas blue by applying coffee grounds to the soil. The coffee grounds make the soil more acidic, allowing the hydrangea to more easily absorb aluminum.
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.