Hydrangea Care 5 tips for the perfect blossom

Eva Monning Eva Monning

Whether it’s watering, fertilizing or correct pruning: if you follow these 5 Hydrangea care tips, your Hydrangea will reward you with healthy growth and abundant blooms.

Blue-flowered Hydrangeas

The better Hydrangeas are cared for, the larger the blooms

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What would a garden be without Hydrangeas? With light green leaves and luxuriant blooms, the subshrubs really get going in early summer in partially shaded corners, under trees and by garden ponds. It’s no coincidence that the Bigleaf Hydrangea (Hydrangea macrophylla), which welcomes summer with its large white, pink or blue ball-shaped flower clusters, is one of the most popular garden shrubs. Yet, the beautiful flowers don’t come from nothing. We’ve briefly summarized the most important Hydrangea care tips so that your Hydrangeas grow healthily and flower freely.

How to plant Hydrangeas

Hydrangeas like slightly acidic, loose, humus-rich soil that retains moisture. A partially shaded, sheltered spot is most suitable for the flowering plants. Hydrangeas have a shallow root system and therefore need a sufficiently large planting hole with adequate distance from other plants with similarly shallow roots. When removing the plant from its pot, any roots that are spiraled around the side need to be removed, as they impede the shrub’s growth. Dig a sufficiently large hole and loosen the soil. The new Hydrangea should be deep enough so the upper part of the root ball is exactly at ground level. Fill the hole with soil and tread down to compact the substrate around the plant. Hydrangeas need plenty of water after being planted. You should also water the plant regularly in the days after planting.

Hydrangea Endless summer

Hydrangeas add some color to the flower bed with their luxuriant flowers

The be-all and end-all of Hydrangea care: plenty of water

Hydrangea can be roughly translated as ‘water slurper’. One of the main characteristics of Hydrangeas is their almost unquenchable thirst. That’s why Hydrangeas are often found naturally by watercourses and damp forest edges. Make sure the flowering shrubs have plenty of water, especially on warm days. Due to its high levels of lime, tap water is not ideal for Hydrangeas. It’s best to water them with rainwater or softened drinking water. During hot summers, the plants go limp in the midday heat. This is a clear sign that they need a lot more water. It’s best to water the plant thoroughly once (twice on hot days), rather than frequently giving it small amounts of water.

Watering Hydrangeas

Hydrangeas need sufficient water to thrive

The right fertilizer

Hydrangeas are heavy feeders and need sufficient nutrients to form their grandiose flowers. To fertilize Hydrangeas, use a special Hydrangea or Rhododendron fertilizer, as this ensures consistently acidic soil.

Blue Hydrangea flowers

Blue Hydrangea flowers don’t appear on their own, but rather by using the right fertilizer

If you want blue Hydrangea flowers, you can change the color of pink Hydrangea macrophylla (such as ‘Endless Summer’) within one to two years by reducing the pH. The flowers turn blue in very acidic (pH between 4.5 and 6), aluminous soil. Plant the Hydrangea in special Hydrangea or Rhododendron soil and regularly add aluminum sulfate, Hydrangea colorant, or Hydrangea fertilizer when watering the plant. Adding potassium alum (available from pharmacies) to the water in spring also works. If you’ve purchased plants that already have blue flowers, they will also need their color refreshed on a regular basis, otherwise they’ll turn pink again. A word of caution: not all Hydrangeas can be turned blue. White and red varieties of Hydrangea macrophylla are generally true to color and do not produce blue flowers!

Take care when pruning

Pruning Bigleaf Hydrangea

The type and timing of pruning depends on the Hydrangea species

To prune Hydrangeas correctly, you need to know which species you’re dealing with. As bigleaf, sargent and Mountain Hydrangeas have buds that were formed during the previous year, they should not be hard pruned in spring, because this will prevent them from flowering. Therefore, simply thin out Bigleaf Hydrangeas and cut off frozen, dry branches and old inflorescences just above the new buds. For shrubs that have grown too densely, you can also remove individual branches close to the ground. In contrast, Smooth Hydrangeas and Panicle Hydrangeas flower on new wood, meaning each branch can be cut all the way back to the last pair of buds. If you’re not sure which type of Hydrangea you have, simply check whether the plant has buds in winter. If it does, you don’t need your garden shears. Tip: Hydrangeas from the ‘Endless Summer’ series rebloom occasionally. If you cut off the old inflorescences after it blooms for the first time, the plant may even flower a second time.

Winter protection for Hydrangeas

In fall, Hydrangea shrubs that have been planted out enjoy a layer of leaves covered with fir tree branches around their root area. Exception: newly planted, young Hydrangeas should be covered in the first winter as a precaution, especially in regions that experience cold winters. Full winter protection is not necessarily essential for older garden Hydrangeas. It is normal for the plant to be slightly affected by frost damage and this is well tolerated. Frozen branches can be cut off in spring. However, low temperatures can have a negative impact on flowering.

You therefore need to be careful with black frost, as Hydrangea macrophylla have buds that were formed during the previous year. These buds freeze to death during persistent, severe frosts and as a result, the plant does not flower in spring. If temperatures are set to drop below 23 degrees Fahrenheit, you should temporarily put a fleece cover over the shrubs. This applies in particular to late frosts when new growth has already started to emerge. Tip: leave dead flower heads on Hydrangea macrophylla over winter. It not only looks pretty, but also protects the shoot tips underneath.

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