Hydrangea: planting care pruning and flowering

Hydrangea is a shrub easy to grow. It produces such an abundance of splendid inflorescences that it is enough to delight all lovers of flower gardens. Let’s find out how to grow the most common species ofhydrangea which is commonly called hydrangea, an appellation without any botanical value. It is mainly used in the horticultural field and it is the one that the general public uses more readily.

Planter un Hydrangea (Hydrangea)

It is ideally in autumn that we plant the Hydrangea, but it is also possible to put it in the ground at the end of spring, even in summer, provided that the risks of frost are removed and that the summer temperatures are not too high.

Planting a Hydrangea purchased in a container is carried out as follows:

  • Soak the root ball in a basin of water to rehydrate it,
  • dig a big enough holeat least twice the size of the clod,
  • Prepare the substrate with the garden soilthree large shovels of decomposed compost and, if the soil is calcareous, mix equal parts garden soil and heather soil,
  • Place a few handfuls of crushed horn reduced to powder then halfway up, fill with the earth/compost mixture,
  • Take the plant out of the basin of water,
  • Untangle the root bun without damaging the roots to facilitate recovery,
  • Install the Hydrangea in the middle of the planting hole, making sure that the collar is flush with the ground,
  • Fill the hole with the rest of the mixture,
  • Pack all around the foot,
  • Water generously.

If one wishes plant multiple topicsthe shrubs must be separated from each other by 90 to 100 cm because after some time they take on a good size.

Cultivation of Hydrangea (Hydrangea)

Hydrangea, commonly known as Hortensia, does not like full sun. It must therefore be displayed between partial shade and shade. For it to flower, this condition must be respected, knowing that a place in the West or North is much preferable to a southern exposure. It can be planted near large trees that will give it all the shade it needs or even near a wall or the house.

This shrub particularly likes acid soils, fresh and humus. But a neutral soil is still preferable to calcareous soil, which must imperatively be cut with land of heather in order to preserve the basic color of its flowers. If you are not careful, blue can very quickly turn pink!

Caring for your Hydrangeas

No need to spend time caring for your hydrangeas to be able to admire their splendid summer flowering, bringing pretty touches of pink or blue to the garden. These are undemanding shrubs.


During the first year after planting, the Hydrangea needs regular and sufficient watering. The soil should never be dry, but you shouldn’t leave your roots soaking in water.

Subsequently, watering from time to time is essential, especially when it is very hot or when there is a severe lack of rain, and it must be more closely monitored throughout the flowering period. In any case, it should be remembered that, whatever its age, the Hydrangea should never run out of water.


It is advisable to install a mulch at the foot of the hydrangeas to maintain a sufficient freshness et limit the development of unwanted weeds. We can thus save a few tens of liters of water over a season and spend less time weeding.

The ideal mulch for the Hydrangea and the one with pine bark because it brings a certain acidity to the earth as it decomposes. It takes approximately 7cm thick for a completely satisfactory mulch.

Addition of heather soil

With the exception of the Breton region where Hydrangeas keep their beautiful blue color without special care, in the other regions of France it is essential to very regularly contributions of so-called heather soil so that this color does not change.


It is advisable to add a fertilizer rich in sulfate d’aluminefrom November to March, in order to complete the action of the heather earth, this type of fertilizer being called bluing fertilizer.

This shrubby plant also needs a fertilizer rich in phosphorus and potash since it promotes flowering while avoiding the softening of the stems. And to bring to the Hydrangea thenitrogen which he also needs, nettle manure is perfect.


Size only applies to young shrubs blooming for the first time. It is in the spring following flowering that care must be taken to cut off all the faded heads, by cutting each stem just above a bud. Of course, we always select the most vigorous buds of the Hydrangea.

Subsequently, the pruning is limited to the removal of weak stems or dead wood, and a rejuvenation waist when the branches are a little too old. In this way, we obtain a renewal of the young stems which will provide more flowers. Be careful, however, to only remove a maximum of three old branches per year. On the other hand, cutting back a Hydrangea of ​​more than 30 cm cancels any flowering the following year since the buds are suppressed at the same time.

Small special mention for the paniculated hydrangea (Hydrangea paniculata) which must be pruned differently so that it produces larger but fewer white panicles: last year’s shoots are to be cut above the lowest pair of buds. However, if you prefer a greater number of panicles even if they are smaller, then it is not necessary to prune the Hydrangea paniculate.

Pests and diseases

Hydrangea is sensitive to mealy bug which occurs in June. It is recognizable by the whitish cottony ovisac that it carries on its back and one can suspect its presence in the honeydew that it deposits on the stems and which attracts ants. The flaky scale insects feed on the sap of many plants and can therefore cause havoc. The plant is sprayed after it has been laid, in June, with a mixture of water and black soap or water and beer. All affected plant parts should be removed and burned.

In very dry and hot weather, the red spiders can invade hydrangeas. Rain watering is enough to make them disappear. Otherwise, you can use a anti dust mite for plants.

Finally, it should be noted that excess humidity can lead to Hydrangea maladies cryptogamiques, that is to say due to a fungus. This is the case of botrytis or powdery mildew or white rot. The use of Bordeaux mixture gives good results in case of botrytis, and to treat white rot, an anti-oidium fungicide is used. To play the prevention card, water only at the foot of the plants without wetting the foliage and make sure to space the hydrangeas sufficiently far apart when planting so that air circulates between the shrubs.

Blooming Hydrangea

Hydrangea is a shrubby plant that blooms profusely as long as the growing conditions meet his needs in all respects. From June to September, each specimen is covered with magnificent flowers of large diameter, which are the pride of all gardeners. Besides, who has never stopped in front of a garden to admire the profusion of hydrangea flowers, highlighting an alley or a terrace? This plant brings great delight without being very demanding.

The wilted flowers must be removed gradually so that the plant retains a good appearance, except for young plants as we have specified in the paragraph reserved for pruning.

You can also create pretty bouquets of cut flowers. They hold up well in a vase, provided that their stems are bevelled and that when installing them in the vase, care is taken to eliminate all the lower leaves that risk soaking in water. It is best to then place the bouquet in a place protected from direct sunlight. It remains to top up the water level every day, which drops rapidly because the Hydrangea flowers in a vase drink a lot.

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