Hydrangeas are typical cottage garden plants with lush flowers. After the long flowering period, regular pruning is called for. When and how to properly cut hydrangeas.
Already in the 18th century hydrangea, or hydrangea, was bred in German-speaking countries and over the years found more and more lovers. No wonder, because the bushes bloom all summer and smaller varieties are quite frugal and very decorative, not only for the garden, but also in larger pots. The care is thereby pleasingly simple. Fertilize from time to time, water regularly (and plenty of it) and pruning once.
The best time for pruning: cut hydrangeas in the spring.
The best time for pruning for all varieties is in late winter or early spring. About the end of February to mid-March, you should tackle this job. See the text below for exceptions.
As with so many plants, the same is true for the numerous hydrangea species: the right date for pruning is important. Many amateur gardeners reach for the scissors in the fall and give each plant a radical pruning. Often the withered flowers are cut away, the ball hydrangea even shortened to the ground.
Some species tolerate being cut in the fall, at least those in mild areas and sheltered locations in the garden. But the majority can suffer significantly. In the case of the popular and common garden hydrangea, for example, the wilted flowers protect the new shoots already formed underneath in the fall and the buds for new flowers from frost.
How your flowers should be cut back depends mostly on which pruning group they belong to. Not sure which hydrangea species you have in your garden? Don’t worry: the cutting group should be relatively easy to identify.
Pruning group one: prune these hydrangeas only moderately.
Pruning group one plants bloom on perennial wood, or “old wood.” They already set new buds and leaves under a cover in the fall. In order not to endanger the new blossoms of the following year, plants of this pruning group are cut back carefully only in spring – in mild spring at the end of February, in harsher ones rather in the middle.
This group includes the garden or farmer’s hydrangea (Hydrangea macrophylla), the plate hydrangea (Hydrangea serrata), the wild form velvet hydrangea or the rough hydrangea (Hydrangea aspera ssp. sargentiana) and its garden form, the giant leaf hydrangea (Hydrangea aspera macrophylla), the typical species that present their inflorescences in relatively flat umbels.
Tip: No matter what variety of hydrangea you cut, pruning shears should be well sharpened.
Furthermore, the selter oakleaf hydrangea (Hydrangea quercifolia, recognizable by its divided leaves) and the climbing hydrangea (Hydrangea petiolaris) are among them.
Test: If you do not know now whether your plant belongs to this group, then simply look in the fall or late winter directly under the flowers that have blossomed. If you see clear thickening here, or if leaves are already peeking out on the shoot in early spring, then the plant in your garden belongs to category one.
And this is how you cut plants of group one
Here you need to remove in the spring only the old inflorescences close, about 1 cm above the top pair of intact buds. If you leave these shoots longer, it not only looks unsightly, the shoots can also die in the upper part; along with bud and new leaves. That is why you should remove this wood.
Speaking of dying: Shoots of the farmer’s hydrangea in particular sometimes do this after a few years. But you can see this immediately in the spring. These shoots are sapless, weak and without buds. Cut back these shoots just above the ground. Tip: You can also take this radical measure if there are too many shoots, in order to thin out the plant in the garden or pot a little.
In some regions or during particularly cold winters, you may not see any new shoots, even though the plant belongs to pruning group 1. Here’s a tip from a professional: Use your thumbnail to scrape away the top layer of bark from a spot on the supposedly dead shoot. If green appears clearly under this, then there is still life in it.
By the way, if flowers of this class are cut more radically, because they are simply too large, old or sprawling, then you must expect that they will not bloom in the following season. However, for rejuvenation, this measure is perfectly suitable.
Good to know: For some farm and garden hydrangeas, color is determined by the acidity of the soil. A pH between 4 and 4.5, i.e. an acidic soil, produces purple or blue flowers, while alkaline soils with a higher pH produce flowers in pink or red.
The exception: cut back Endless Summer
There are numerous hydrangea cultivars. One of them is the fairly new cultivar “Endless Summer”. It is a special cultivar that blooms on both old and annual wood. When it was introduced in 2003, this was a sensation for a farmer’s hydrangea. It blooms from spring to late fall.
On this variety after the winter is usually removed only the withered flowers. Optionally, and if the Endless Summer becomes a little lazy in the summer or the flowers wilt too early – but this may be due to lack of water or fertilizer – you can cut back individual shoots until the next budding. The gardener calls this remontage and aims with the measure a new flower formation still in the same year.
The same applies to the likewise newer cultivars of the “Forever & Ever” series.
Pruning group 2: these hydrangeas cut them vigorously
For plants in group two, all shoots are cut just above the ground in early spring. Here, only one pair of eyes needs to remain standing. In sheltered locations and mild areas, this can also be done in late fall, as these two species are more frost resistant. From these two eyes hydrangeas sprout completely and always with two shoots.
This pruning technique applies to ball or snowball hydrangeas (Hydrangea arborescens, “Annabelle”, “Grandiflora” and the rather rare variety “Hayes Starburst”), which also form their flowers on the new wood, as well as to the panicle hydrangea (Hydrangea paniculata, e.g. “Vanilla Fraise” or “Lime Light”) with its conical, imposing flowers. Both varieties nevertheless sprout up to 1.5 m tall.
Panicle Hydrangea: Exceptions prove the rule
With the panicle hydrangea with such a radical cut really remove and cut off everything? It does not necessarily have to be. It is also enough if you cut it above a bud at a height of about 40 cm. In addition, you can also completely abandon the pruning. Then it has a chance to grow to about 2.5 m in height.
However: the flowers are then not as large for a long time and the number of shoots that form over the years can seem a bit confusing. Do without cutting is worth it when planting the panicle hydrangea as a screen.