The beautiful hydrangea blossoms only emerge with optimal care. We show everything you need to know about watering, cutting, and fertilizing hydrangeas correctly.
Hydrangea (Hydrangea) can be a real beauty in the garden. But sometimes it is not that easy to achieve the abundant bloom every year as desired. You have to deal a little with the care of the flowers to avoid the loss of flowers or yellow leaves on the hydrangeas. By following our expert tips, you no longer have to worry about such failures.
Hydrangeas are reliably blooming classics in the garden – but only with the right care. From watering and fertilizing to supporting the large inflorescences of hydrangeas – here you will find out everything about the correct handling of the beautiful divas.
Table of Contents
Hydrangeas are very thirsty. Regular watering of the hydrangeas is therefore essential, especially for specimens in planters. But hydrangeas that have been planted in the bed are also happy about an occasional watering. A lack of water is quickly noticeable in hydrangeas: drooping leaves and flowers are the first signs. Before that, you can also observe that the color of the foliage turns into a significantly darker green.
How to water hydrangeas:
- Check the soil/substrate regularly; when it starts to dry out, it is time to give water
- It is best to water with rainwater, tap water is often alkaline and raises the pH value in the soil
- Do not pour everything at once like a monsoon, but rather distribute the irrigation water over several small doses
- Avoid waterlogging, so provide tubs with drainage holes
- Hydrangeas in the tub may need to be watered several times a day in summer, preferably in the morning or evening
- In winter, the hydrangea does not need to be watered
Hydrangeas should be fertilized organically or organically-minerally. Purely mineral fertilization is possible but damages the plant in the long term by deteriorating the soil quality. It also makes trace nutrient deficiencies more likely.
How to fertilize hydrangeas:
- Organic fertilizer for planting should be evenly distributed in the planting hole and poured well.
- Hydrangeas outdoors are sufficient to be fertilized with organic or organic-mineral fertilizers in the year, which should be strictly between March and May. Subsequent fertilization can endanger the flowering of the following year and, if the nitrogen application is too high, also affect the entire plant through frost damage.
- Pot hydrangeas are fertilized twice a year because of the lower substrate volume: they receive two-thirds of the fertilizer application between March and May, the last third between June and August. The use of organic, potassium-rich fertilizers is particularly important on the second appointment. Nitrogen is released from these more as needed and does not lead to the formation of new shoots susceptible to frost. The potassium increases frost tolerance, it serves as a kind of antifreeze in the vacuoles of the cells.
When supplying nutrients to hydrangeas, the pH value of the soil must always be taken into account. The richly blooming beauties get along much better on acidic soil than on neutral or slightly alkaline soil. A pH value of around 4.5 is required for blue flowers to develop. The very frequent iron deficiency in hydrangeas is also related to the acidity of the soil: If this is not sufficiently acidic, iron is poorly available for hydrangeas. Keep this in mind when planting and use, for example, rhododendron soil, oak leaves, or coniferous soil to keep the soil acidic.
Our Gardender organic hydrangea fertilizer is organic-mineral and protects your beloved hydrangeas from frost damage thanks to a potassium-emphasized nutrient composition. The flowing implementation promotes even growth and flower formation. To prevent an iron deficiency, this micro-nutrient element is also included, so that even small pot volumes do not become depleted.
You can find detailed information on fertilizing hydrangeas and dosing instructions here in our special article.
The right cut is essential for beautiful flowers. Hydrangeas can be cut either in the fall or in the spring. To determine the right time, one should first know which type of hydrangea it is. Because farm hydrangeas (Hydrangea macrophylla ) and oak leaf hydrangeas ( Hydrangea quercifolia ) develop their flower systems for the next year in autumn. So they bloom on last year’s wood. If you cut back too much here, this can mean the loss of the beautiful flower.
Panicle hydrangeas ( Hydrangea paniculata ) or snowball hydrangeas ( Hydrangea arborescens ), on the other hand, bloom on so-called annual wood. That is, they form their flowers the same year they bloom. These two popular hydrangeas are among the species that can be pruned back undisturbed.
As a rule, you can rely on the fact that all hydrangea species offered in the USA are reasonably hardy. In this case, to some extent means that frost damage is unfortunately quite possible and can also affect the flowering. To avoid this, you should note the following:
- A protected place in partial shade should be chosen when planting.
- Winter protection made of leaves, a jute sack, fir branches, or mulch protects the plant. Above all, always cover the outer shoots close to the ground.
- Fertilization with mineral nitrogen is taboo from mid-July. Organic fertilizers can be used well into August.
- The fertilizer used should have a sufficiently high potassium content, as this is essential for frost resistance.
- Even if the temperatures rise, you should not completely remove the winter protection until the ice saints (11th to 15th May) have passed. Have the burlap sack ready for frosty nights. Of course, exposing the plant in the first warm weeks is possible and important.
- Hydrangeas in pots are protected in the same way as their relatives outdoors. In addition, they should spend the winter in protected garden areas. Containers with a diameter of fewer than 35 centimeters are better to overwinter frost-free (3 – 5 ° C) in a shed or garage.
Tip: When buying hydrangeas, pay attention to the condition in which they are. Some garden centers offer plants that bloom in the greenhouse that are still in bloom in autumn. Hibernating these outdoors inevitably leads to severe frost damage, because to produce attractive plants, they are often fertilized far too abundantly during cultivation. Tree nurseries often offer slightly more expensive, but higher quality goods and better advice.
Snowball hydrangeas ( Hydrangea arborescens ) in particular have a tendency, due to their growth and large inflorescences, to lean towards the ground due to the excessive load during flowering. But also the classic farmer’s hydrangea (Hydrangea macrophylla ) sometimes droops its head, although it does not lack water – especially if it is in too shady locations and the shoots are rather long and unstable.
Of course, hydrangeas look all the more impressive when they stand upright and their blossoms stretch up into the sky. There are two ways to help hanging hydrangeas grow upright:
- Support hydrangeas with bamboo sticks
- Support hydrangeas with perennial rings or perennial holders
You can support the individual shoots of the hydrangea with a bamboo stick. This helps to achieve more stability, but it also looks ugly very quickly. A good alternative to bamboo sticks is the perennial rings or perennial holders available in specialist shops. The circular perennial rings with a fastening rod in the middle can be used to stabilize smaller hydrangea specimens. Larger plants are better supported with semicircular perennial holders and held in an upright position.
Pests and diseases on hydrangeas
With good care, hydrangeas are usually not particularly susceptible to disease and pests. If your hydrangea is nevertheless affected, we will show you below what you can do against yellow leaves and mealybugs on hydrangeas.
Yellow leaves on hydrangeas: lack of iron
If the leaves of your hydrangea turn yellow, the cause may be an iron deficiency, also known as chlorosis. Such chlorosis is particularly common in hydrangeas. The reason for this is usually a lack of nutrients. The missing nutrient in hydrangeas is almost exclusively iron, although there is almost always enough of it in the natural soil. The reason for the deficiency is not the lack of iron in the soil, but that the hydrangea cannot absorb the iron present.
This occurs in hydrangeas when the pH is too high. The bog plant is adapted to low pH values around 4 – 5.5. A pH test is necessary so that the pH value can be correctly determined. If the measured pH value is too high, it can be reduced with rhododendron earth, lime-free peat, or Epsom salt. It is best to plant hydrangeas in pots in pure rhododendron soil, so you don’t have to worry about chlorosis.
Mealybugs on hydrangeas
Mealybugs ( Pseudococcidae ) are also often called mealybugs and particularly like to sit on our hydrangeas. They are very easy to spot because they are surrounded by a white web that resembles tiny white hairs or fluff. The mealybugs attach themselves to the plants and then ingest the sap, where they can transmit harmful viruses to the plants.
They also excrete the sticky honeydew, on which fungi often still settle. Therefore, it is not uncommon to discover sticky spots on the plants, which are often discolored dark or black by the fungi. As the lice suckle the hydrangeas, the infected leaves turn yellow and eventually fall off. If the infestation with mealybugs is very strong, the hydrangeas can even die.