Hydrangea – care, pruning, propagation

It is so difficult to provide the hydrangeas with the right soil – you often hear that. Just don’t believe it! Actually, hydrangeas have no special requirements at all for the soil in which they are planted. They grow excellently in loamy soil that is permeable enough not to retain water. Any other humus-rich soil that retains moisture well and is sufficiently airy seems to be just as suitable. And even in real “sand boxes”, like the gardens in Berlin and Brandenburg, for example. B. are often, you can admire magnificent hydrangeas.

The average hydrangea doesn’t care much about soil pH either. Contrary to every other claim, hydrangeas thrive in soils with a pH of 8 (clearly basic) to 5 (clearly acidic). You can even see hydrangeas in mountainous regions with extremely calcareous soil. Admittedly, however, they tend to do better in lowland heather soil, which tends to have a more acidic pH. In any case, this applies to all reddish colored hydrangeas. The “blue-flowered” hydrangeas need a special soil to maintain the blue flower.

location

The hydrangea accepts locations where most other flowering plants would not show a variegated leaflet. It likes partial shade, yes, it can even stand in the shade, giving the gardener the opportunity to transform the otherwise rather dreary areas of the garden into blooming landscapes (for real this time). An excellent location for a hydrangea is z. B. the otherwise mostly bare space under a deep-rooted tree. Here she is protected by the lush canopy from the midday sun, which quickly becomes too hot for her. Heavy rain showers are also weakened at the same time, which pleases the sprawling inflorescences. However, hydrangeas do not insist on “darkness”, they always like the morning sun and evening sun; if the soil is moist enough or is continuously watered,

Whether it is placed in the garden at all or should be planted in a bucket depends on the variety. Farmer’s hydrangeas and plate hydrangeas are “almost hardy” in Germany, whenever it gets really cold, they need winter protection in the soil area, the shoot tips often freeze off. Native to Japan, panicle hydrangeas are more frost hardy (and will tolerate most direct sun, too).

Fertilizer, water, care & Co

If the fertilization is not right, you will notice it anyway: If your iron is missing or if it cannot utilize existing iron (e.g. because there is too much phosphorus in the soil) or if the soil is too basic, the hydrangea will usually show it a chlorosis. So she gets light green to yellow leaves with green veins. You could now remedy this chlorosis by adding synthetic substances. There is e.g. B. liquid iron fertilizer that can be sprayed on the leaves. At this point at the latest, a soil test is recommended. Otherwise, with all the additives, you quickly end up in an endless vicious circle.

The average German soil is also rather well supplied with iron. An iron fertilizer could then be more harmful (the ferrous sulphate it contains is also sold as a moss killer and is certainly not good for some other plants either). And against the excessively high pH value, it is probably also much smarter to apply a compost that acidifies the soil somewhat (coniferous compost or coffee grounds) than to deal with artificial acidifiers or vinegar.

If you don’t feel like all the numbers and calculations, it’s best to switch to organic fertilization anyway. This is gradually applied to the ground. Then at some point you will no longer have all the trouble with the jumping soil values, but simply bring out compost and maybe a few horn shavings from time to time (not from August, by the way, a lot of nitrogen makes the plants susceptible to frost damage).

Unless you insist on blue hydrangeas, and also that those hydrangeas keep their blue blooms. Then you need to pay close attention to the soil, it needs an acidic pH of 5.2-5.5 and aluminum. You can admit the latter by getting alum = aluminum sulphate in the pharmacy or by buying so-called hydrangea blue. The acidic soil (please no peat, there are enough substitutes today) must be maintained by appropriate fertilizers, or you make an acidic compost. You may only water here with very soft water (rainwater). Of course, you can also do without all these circumstances, then your blue hydrangeas will bloom beautifully pink to pink.

Special hydrangea varieties

In addition to our popular garden hydrangeas and related hydrangeas, which can be found in every garden center, there are some interesting varieties among the approximately 70 types of hydrangea that can be cultivated here. For example the velvet hydrangea, viburnum hydrangea, climbing hydrangea and the ‘Endless Summer’ hydrangea.

pruning hydrangeas

A whole group of hydrangeas can do without major pruning measures: all garden or farmer’s hydrangeas (Hydrangea macrophylla), plate hydrangeas (Hydrangea serrata), giant-leaf hydrangeas (Hydrangea aspera ‘Macrophylla’), oak-leaf hydrangeas (Hydrangea quercifolia), Velvet hydrangeas (Hydrangea sargentiana) and climbing hydrangeas (Hydrangea petiolaris) are perfectly happy if you remove the old inflorescence in early spring (just above the first pair of new buds) and thin out the whole plant a little if necessary (oldest shoots up to cut back to the ground). With this cut, all dead shoot tips are cut off directly above the first healthy blossom. If you are unsure, you can use your fingernail to test whether a shoot is still alive:

These hydrangea species already start sprouting in the old year for the next year, which would otherwise be cut away. If any of these hydrangeas have grown too large, you can cut away more. But then you may have to do without flowers altogether the following year. From this group, the oak leaf hydrangeas are best pruned. With the climbing hydrangeas, you would then have to make sure that the shoots do not strive away from the masonry. Then a cut is necessary so that the climbing hydrangea does not fall off the support with its self-produced mass.

Panicle hydrangeas (Hydrangea paniculata) and snowball hydrangeas (Hydrangea arborescens), on the other hand, form their flower buds on the new shoot and bloom in the same year. Accordingly, they are circumcised. With these hydrangeas, you can prune all the shoots as early as late autumn. The leftovers should always contain a pair of eyes, which will then sprout in the next season. If you wish, this pruning can also be done in early spring. If you always pay close attention to the pairs of eyes, you will double the shoots every year. This can eventually lead to the crown becoming too dense. Then simply cut out a few weak or crooked shoots entirely.

multiply hydrangeas

Common hydrangea species are easy to propagate from cuttings. Then you would have to cut off some of the newly formed shoots (without buds) in early summer. These are now divided into short pieces with two pairs of leaves (one above, one below). The lower leaves have to go. Roots should develop here. To do this, it is best to first put this end in rooting powder and then a few centimeters deep in a pot with potting soil. This soil must be well moistened. Then the pot can be covered with translucent foil. He now wanders into the garden, under a tree, e.g. B., or on the terrace in a shady place. Now all you have to do is keep the pot evenly moist and air it out every day, after which the first roots should have formed after about 14 days.

When they are strong enough (after another 14 days), you can remove the foil cover. You should bring the young plants indoors in the first winter, as they are still very sensitive to the cold. It would be best for them to give you a fairly cool place now so that you are prepared for the winter chills here with us. After the first hibernation, they could then be planted in the garden.

Some hydrangea varieties make it even easier for you: they occasionally shoot out on the sides, which you can then cut off and plant.

Growing hydrangeas from seeds, on the other hand, will be more of an ambitious undertaking: Buying the seeds will not be easy in Germany, at most you should be able to bring seeds with you from a vacation in Portugal. If you want to continue propagating your own hydrangeas, this could be even more difficult. Because the large flowers of the hydrangea are deceptive, they consist largely of sterile pseudo-flowers that are only there to attract insects with their colorful sepals. The actual fertile flowers are very inconspicuous, they are well hidden in the center of the pseudo flowers. If anything, many cultivars only show the large but sterile pseudoflowers and do not develop seeds.

Hydrangeas overwinter

The “almost hardy” garden hydrangeas should get winter protection in the root area. In very harsh winters, you should also protect the crowns to keep the dying shoots low. These hydrangeas also do not like late frosts in spring, as this could freeze the young shoots with the beginnings of the flowers, so a cover is recommended.

Hydrangeas in small tubs must be frost-free over the winter, but can tolerate cold temperatures of around 3 degrees. If the pots already have a diameter of about 40 cm, these hydrangeas with winter protection can spend the winter time in any wind-protected place in the garden. The climbing hydrangeas usually do not need winter protection at all.

Pests and diseases of hydrangeas

If hydrangeas in the garden suddenly drop their flowers, it may be due to a lack of water supply. In summer, however, this is often a completely normal protective reaction to too much sun. The drooping leaves immediately reduce evaporation from the plant. In such a case, if the soil is wet, all you have to do is wait for worse weather.

Otherwise, hydrangeas are pleasantly resistant to diseases and pests, at least if you keep them optimally. If they suffer from deficiencies, spider mites, scale insects or aphids sometimes show up on indoor hydrangeas rather than outdoor specimens. You can often keep such an infestation at bay with mechanical measures (shower off, collect) until the indoor hydrangea can be planted in the garden in summer.

An unpleasant hydrangea disease is powdery mildew, against which it is necessary to use a whole range of control measures.

Conclusion
Hydrangeas are among the most beautiful plants that delight us in the garden with lots of large flowers. With the special feature that the hydrangeas also show flowers under lighting conditions where many other flowering plants only produce green leaves. A tip: if you cut off a few branches from your hydrangea after it has been cold for the first time and leave them in a cool place until the flower buds swell, these blossoms will also open when you place these branches in the warm living room. In principle, you can cut between autumn and spring, it depends on the branch on the bush having received a strong cold stimulus.