Maintaining and pruning hydrangeas

Hydrangeas are among the most popular garden plants and complement many design styles. If you want to plant a romantically rustic cottage garden, you can use mophead hydrangeas. If your garden is to be more modern but still blooming, then you enrich it with luxuriantly flowering snowball hydrangeas – for example, the variety 'Annabelle' belongs to this type of hydrangea.

To ensure your hydrangeas thrive, bring you joy, and require as little work as possible, you should choose the right location and care for and prune them properly. We'll show you what hydrangeas need to feel comfortable.

Choosing the right location

Hydrangeas prefer moist and humus-rich conditions. No wonder, as they originally come from the deciduous forests of East Asia, Chile, and North America. While some hydrangeas in our gardens can tolerate sunny and dry locations, they always prefer a semi-shaded spot with sufficient soil moisture. Their botanical name, Hydrangea, comes from the Greek, and means 'water pitcher' or 'water drinker,' a clear indication of the shrubs' preference for ample water.

So, give your hydrangea a semi-shaded spot, especially since the mophead hydrangeas are well placed in north or west-facing locations. Meanwhile, panicle, snowball, and oakleaf hydrangeas can be planted in sunny spots, as long as the soil isn't too dry and you water regularly. Improve poor soils with compost and cover the ground with mulch to reduce rapid evaporation. If you shred your green waste with a shredder, you can produce your mulching material. The AXT Rapid 2000 from Bosch, for example, handles this task efficiently and quietly.

Before planting, find out how large your hydrangea can grow. Mophead hydrangeas typically reach about 1.5 to 2 meters in height and width. Panicle and lacecap hydrangeas can reach heights of 3 to 4 meters depending on the variety. The actual size of your hydrangea will depend on its location, care, and pruning. Leave enough space around small young plants for the hydrangea to develop undisturbed, so it won't need to be transplanted later due to lack of space.

Planting hydrangeas

Before planting your hydrangea in the garden bed, you need to carefully remove it from its planting pot, also known as a container. Sometimes, the potting soil is heavily rooted, and the hydrangea roots may have grown spirally along the edge of the pot. You should loosen these roots before planting or trim them if necessary.

Dig a planting hole in the bed that is approximately twice the size of the root ball of your hydrangea. Then, place your hydrangea in the planting hole so that the top of the root ball is level with the surface of the soil, ensuring that you plant your hydrangea at the same depth as it was previously in the planting pot. If necessary, if you don't have good soil quality or the right pH level, dig the hole slightly larger, fill it with high-quality potting soil or specific hydrangea soil, and then place the plant on top. Once your hydrangea is in the planting hole, fill the remaining gaps in the hole with potting soil, hydrangea soil, or the excavated soil. Water the soil thoroughly to close any air pockets in the soil and ensure that the hydrangea roots have sufficient contact with the soil and add more soil if needed. Then, you can form a watering ring around the hydrangea by creating a small mound of soil around the plant. Water can be poured into this watering ring and will not flow away to the side. After planting, you need to water your hydrangea thoroughly, and in the days following planting, the soil should not dry out.

If you want to keep the hydrangea in a pot, you can find information here.

Tip: Hydrangeas are considered mildly toxic. If you have sensitive skin, it's advisable to wear gloves when handling hydrangeas, whether planting or pruning, to protect yourself.

Watering hydrangeas

Hydrangeas are thirsty garden inhabitants. Water them daily in summer, and for potted plants, you should even water them twice a day during hot weather. If your hydrangea leaves and flowers are drooping, it's a sign that they urgently need water. The best watering option is collected rainwater, which you can conveniently use with a battery-powered rainwater pump. If you're using groundwater, check if it's not too rich in calcium.

In general, there are several things to consider when watering your garden, such as the right timing, the appropriate amount of water, and the right type of water. You can find all this information here, including different watering methods.

Fertilising hydrangeas

Hydrangeas need plenty of nutrients to grow. They are what we call heavy feeders. From spring until the end of July, you can provide your hydrangeas with rhododendron fertiliser, organic fertiliser, or specialized hydrangea fertiliser. Do not fertilise later than the end of July so that the shoots can mature and harden before winter, preventing them from being too soft when the first frost arrives.

This is how blue hydrangeas are fertilised

Why is my blue hydrangea suddenly blooming pink instead of blue? You may have wondered about this too. This happens because the flowers of some mophead and lacecap hydrangeas change their colour depending on the pH level of the soil. In acidic soils, they bloom blue. If the pH level of the soil is higher, they bloom pink. So, if you want to have (or regain) a blue-flowering hydrangea, you need to keep the soil acidic and preferably also supply aluminium sulphate. The more acidic the soil is, the more aluminium sulphate the hydrangeas can absorb, and the aluminium ions ensure that the flowers turn blue. There are combination products available in stores that contain both fertiliser and aluminium sulphate. It's best to use this type of fertiliser for your blue hydrangeas to maintain their colour. Pay attention to this when selecting fertiliser.

Winter protection for hydrangeas in beds and pots

If you've planted your hydrangea in the garden bed, and it's well-rooted and not too exposed, it should withstand the winter well. Typically, some branch tips may freeze back but you can easily trim these dead areas in early spring. In areas with very strong frost or in harsh conditions, you can wrap your hydrangea with pine branches or winter protection fleece to shield it from the cold temperatures. A homemade plant cover can also help sensitive or smaller hydrangeas.

If your hydrangea is in a pot on the terrace or by the front door, you should definitely protect it from frost in winter. Wrap the pot with fleece or coconut mats and protect the branches with fleece. You can also place the pot in a box, ensuring that water can drain out, and fill it with leaves for additional insulation against freezing.

Find more tips here on how to make plants winter-proof and information on how to prepare your garden for winter here. Has your hydrangea suffered in winter? Learn here how to rescue frost-damaged hydrangeas.

Propagating hydrangeas

If you want to propagate your hydrangeas yourself, you can do so in early summer by taking cuttings. To do this, cut off shoot tips with two pairs of leaves. Trim the tip of your cutting and remove the bottom pair of leaves by gently tearing them off. Then, shorten the upper two leaves by half. If you like, you can dip the cutting into rooting powder, which aids in root formation, but it's also possible without it. Plant the cuttings in pots filled with potting soil, burying them deep enough so that the lower pair of nodes, which now have no leaves, are a few centimetres deep in the soil. Gently press the cuttings into the soil. Lightly moisten the potting soil.

Place the cuttings in a small greenhouse or wrap them with plastic to maintain high humidity. The cuttings will develop roots after about a week, and you can plant them in the garden next spring.

Do you want to get more out of your plants? Then read here about Regrowing and how you can propagate succulents or bamboo.

Pruning hydrangeas

To ensure your hydrangeas bloom abundantly and remain healthy every year, you should prune them regularly. Since there are different types of hydrangeas that differ in how and when they produce their flowers, specific pruning methods are applied accordingly. For example, you would prune a mophead hydrangea differently than a panicle hydrangea, to which the popular white variety 'Annabelle' belongs.

For better clarity, hydrangeas are divided into two pruning groups. We'll show you which types of hydrangeas exist and which pruning group they belong to. 

The right time for pruning hydrangeas

For all hydrangeas, it's best to prune them at the end of February or beginning of March. Depending on the diameter of the branches, you can use pruning shears like the EasyPrune from Bosch (up to 25 mm branch thickness), loppers, or even a cordless garden saw like the Keo from Bosch (up to 80 mm branch thickness).

Don't reach for the shears in autumn, as the faded blooms of hydrangeas look beautiful even in winter, covered in frost or snow, adorning your garden.

Pruning hydrangeas of pruning group 1

Pruning group 1 includes all hydrangeas that set their flower buds for the next year in the previous year. This means that in spring, you should avoid cutting back new shoots of these hydrangeas as doing so would also remove the flower buds, and your hydrangea wouldn't bloom in the same year. Therefore, for the following hydrangea varieties, you only prune the faded blooms just above the first pair of green buds.

Hydrangeas of pruning group 1 (only remove faded blooms):

-Mophead Hydrangea (Hydrangea macrophylla)

-Lacecap Hydrangea (Hydrangea serrata)

-Velvet Hydrangea (Hydrangea sargentiana)

-Climbing Hydrangea (Hydrangea petiolaris)

-Oakleaf Hydrangea (Hydrangea quercifolia)

If you remove branches to thin out the shrubs in early spring when they have become too dense or large, you will have to forego the flowers in the same year. However, such a drastic pruning is certainly possible.

Exception: Prune repeat-flowering varieties like 'Endless Summer'

The newer, repeat-flowering varieties technically belong to the mophead and lacecap hydrangeas, but they set their flower buds in the same year they bloom. Therefore, they bloom even if pruned in spring. If necessary, you can also prune these varieties more heavily and still enjoy their flowers in the same year. Additionally, like repeat-flowering roses, you can deadhead them after the first bloom to promote new flower production.

Some of the repeat-flowering hydrangea varieties include 'Endless Summer', 'The Bride', 'Twist'n Shout', 'Forever & Ever', and 'Bloomstar’.

Pruning hydrangeas of group 2

Hydrangeas in pruning group 2 include those that form buds on the stems that they have produced in the same year. You can therefore prune these hydrangeas back to just above the ground in early spring, as new, flowering shoots will develop again. However, you must leave at least one pair of buds, which is the point from which new shoots will emerge. If you prefer not to cut your hydrangeas so low, you can prune them less severely.

Hydrangeas in pruning group 2 (remove all shoots):

-Panicle hydrangeas (Hydrangea paniculata), including varieties such as 'Little Fraise', 'Unique', 'Pinke Winky', 'Limelight', 'Vanille Fraise', 'Bobo', and 'Bonfire’.

-Smooth hydrangeas (Hydrangea arborescens), including varieties such as 'Annabelle', 'Strong Annabelle', 'Pink Annabelle', and 'Incrediball'.

Since this pruning method results in two new shoots emerging from each stem, your panicle or smooth hydrangea will become very dense over the years. If necessary, you can also completely remove individual stems by cutting them to the ground without leaving a pair of buds.

You can find more information on planting and pruning shrubs here or here.

If you want to know more about when certain gardening tasks need to be done, you can find that information in our garden calendar, which provides the right timing for all important activities.