Hydrangea - Hidrangea


The hidrangea is a genus composed of 80 species of shrubs and climbers, floriferous, evergreen or deciduous. Hydrangeas are rustic plants, which resist even at low temperatures, but when the cold is very intense, they need protection. Among the different species of hidrangea, the climbing ones, are the most resistant.
Hydrangeas are among the most widespread and loved shrubs: they combine extreme ease of cultivation with a long and showy flowering.
They are eclectic: they can become part of flowerbeds and borders or be used in purity as isolated specimens or in groups. Given the many species and cultivars available, it is even possible to create gardens of hydrangeas only, without the danger of being monotonous.
The propagation is very simple and allows us, within a few years to set up beautiful hedges.
In the right conditions, and with some extra attention, it is possible to grow them also in pots, cheering up balconies and terraces.

Cultivation techniques

Hydrangeas are planted during the month of October / November, or March / April. The ideal soil must be fresh, enriched with mature manure, with peat or with premixed soil suitable for acidophilic plants. We recommend planting them in semi-shaded positions (for example near a wall or a large tree) with the exception of the Sargentiana species which, if the atmospheric and soil humidity is not high, must be planted in the complete shade.
In spring, it is good to give a well-decomposed organic fertilizer to the hydrangeas.
In the apartment or in the greenhouse the hydrangeas are cultivated using pots of about 25 cm. In the first months of the year vegetative growth can be stimulated, bringing the plant in an environment with a temperature of about 10 ° Celsius and distributing more water. After the first flowering, the hydrangeas must be transplanted in the garden, in sheltered positions.

Characteristics of hydrangeas

Hydrangea, the botanical name of the hydrangea, is a flowering shrub native to eastern Asia and northern America. The dimensions can vary greatly: they range from a height of 80 cm for the smallest, up to more than 10 m for climbing varieties. The inflorescences are collected in corymbs or panicles. Those that we identify as "petals" are actually modified bracts. The real flower is very small and insignificant. The most striking inflorescences are composed almost exclusively of sterile flowers. The fertile ones are clearly visible, for example, in the center of those with the "lacecap" shape.


Height at maturity

From 1 to more than 10 meters
Type of plant Deciduous or semi-persistent shrub or creeper
Cultivation / Maintenance Simple / low
Exposure Half shade-light shade
RusticitŠ° Rustic, suitable up to 1000 meters s.l.m.
Ground Forest land, rich in organic matter
Ph of the soil Acid to neutral
Irrigation / soil moisture Frequent / always fresh, but well drained
use Borders, isolated specimen, groups, hedges, vases


For the multiplication of hidrangea or climbing hydrangea plants, it is necessary to take, in the months of June and July, cuttings of about 8 cm from the lateral jets and plant them in a mixture of peat and sand in equal parts in a cold greenhouse or in a caisson. The rooted cuttings can be potted singularly, in containers of about 10 cm, and repotted in October.

Shrub species:

Shrub cuttings are taken in August and September, and must be about 10-15 cm long. The rooted cuttings are placed in 10 cm pots and placed in a cold container. The seedlings are transplanted in the spring. To obtain more vigorous plants, when three pairs of leaves have formed, the buds can be trimmed. Plants with a single stem multiply by apical cuttings 10 cm long that are harvested in September.


Hydrangea plants do not require regular pruning (this applies to most species) except for the removal of appasite flowers, to be carried out in March or late summer. We recommend, however, to remove the weakest branches in February, to thin the plant and, in the same month, to cut the flowering stems of the previous year of the arborescense and paniculata species in the middle of their length.

Parasites and Diseases

The hydrangeas can be damaged by the aphids and in the greenhouse by the red spider of the greenhouses. The most common diseases are chlorosis and the small family. Hydrangea plants can also be affected by molds that can compromise their health.


Hydrangea plants are a rather rustic variety and can withstand short periods of drought. In the summer season it is good to intervene regularly, supplying water before the soil is completely dry. During the winter the watering should be reduced, especially for the specimens planted in the ground.

The color of the hydrangea flowers

The corymbs can be of many different colors: white, red, yellow. The most common species (macrophylla, serrata ...) have mostly pink, blue or purple. It is known that these nuances may vary on the same plant depending on the characteristics of the soil. With acidic substate, the plant assimilates more easily the aluminum salts, indispensable for the blued shades. If the soil is neutral or basic, the bracts will take on pink or purple at most.

Exposure and climate for Hydrangeas

The ideal exposure for hydrangeas is the partial shade. They bear a few hours of direct sun, possibly during the morning, but the light and the heat of the afternoon can weaken them heavily ruining the flowers prematurely and burning the leaves. Having said this it should be noted that in the mountain areas, fresh and rainy, they grow very well even in full sun; in the South and on the coasts, on the other hand, we need to consider even more sheltered locations, where the sun rarely comes.
If the heat is their enemy, we must not fear the cold. They overcome the most rigid winters without particular precautions if not a good mulching (and postponing the prunings in the spring).



March / October-November (Center-South)
Composting March
Pruning November to March
Talea August September
repotting March April
Flowering June September
Flowers collection by drying August September

Land and planting

The popularity of hydrangeas alone makes us understand that these are extremely adaptable plants and that they perish only in really serious cases. To have them luxuriant and flowery it is essential to provide them with a substrate capable of retaining moisture, rich in organic substance, well ventilated and possibly with an acid reaction. To this we add that drainage must be efficient because frequent watering must never cause water stagnation.
If the soil is of medium texture or slightly clay we can extract it and mix it with 50% of soil for acidophilic. We also add a good quantity of well decomposed flour manure. Alternatively, it is possible to replace it completely, even only with a product for acidophilic mixed with organic substance.
The plant can be done in autumn or spring (where winters are harsh). Dig a large and at least 50 cm deep hole and prepare a thick gravel-based draining layer on the bottom. Place the plant, fill the hole, compact it carefully and distribute plenty of water.

Irrigation and humidity

Hydrangeas love an always fresh substrate. In almost all of Italy irrigation, on stamped plants, can be superfluous, particularly in spring and autumn. With suitable positioning and ground normal rainfall is sufficient to meet its needs. At the end of hot days it can happen that the plant has a loose appearance. We wait for the morning before distributing water and we irrigate only if its appearance has not changed. An important aid can also come from environmental humidity: it may be useful to proceed with slight vaporization of the foliage, towards the time of sunset. If the situation is repeated too often, we take into consideration the moving to a more sheltered position and the replacement of the substrate.
During the summer, interventions may instead become indispensable: we count on distributing at least 20 liters of water per specimen, three times a week.
To avoid the onset of leaf chlorosis, caused by the accumulation of calcium in the substrate, it is advisable to use as much rain or at least decanted water as possible and to distribute iron sulphate from time to time.

Hydrangea fertilizers

The fertilizations are indispensable for vigorous growth, abundant flowering and maintaining a vital and airy substrate. For the hydrangeas it is good to intervene in February by distributing abundant pelleted manure within the entire area covered by the foliage. We will absorb it to the ground with a light hoe.
Very useful, however, is also to provide a sufficient dose of macro and microelements: the ideal products are those specially formulated for hydrangeas, in slow release granules. Usually only one administration is necessary, at the beginning of spring


Pruning is not essential. With hydrangeas it is better to avoid intervening rather than intervening too much, causing a vintage with scarce blooms.
However you can decide whether to proceed in the fall or spring (choice of choice for those who live in areas with a harsh climate). The most widespread varieties bloom on the branches of the previous year: the dead, dead or weak branches must be eliminated and the apical inflorescences cut off at the level of the first two buds from above. The fully formed plants (over 6 years of age) must be progressively rejuvenated by removing about 1/3 of the vegetation each year, choosing for this the branches that now seem to be too branched. We always try to open the center of the sample a little so as to favor the passage of air and light.

Pests and diseases

The most common problems are powdery mildew, gray mold and cochineal.
The former are prevented and dammed limiting moisture on the foliage and on the ground. Vaporizations with sulfur-based products can be useful.
Scale insects can be removed manually with alcohol-infused cotton buds. In the event of severe attacks, mineral oil may be used, possibly added with a systemic insecticide.
Individuals kept in pots on terraces and sunny balconies are frequently hit by red spider mites. It can be prevented by providing a more shaded exposure and increasing environmental humidity with frequent vaporizations. In extreme cases we resort to acaricides.

Hydrangea propagation

As we have said, getting new hydrangea seedlings is extremely simple. The most used method is certainly the cutting.
Proceed in August, when the plant is in full bloom:
- You choose a branch of the year, robust and with a good diameter, but without a flower.
- We cut about 20 cm from the base near a pair of leaves, where the fabric is tender.
- We eliminate all the leaves, except two on the top.
- We insert the branch in a substratum obtained with soil for sowing and sand, in the same quantity. We leave about 10 cm between one stem and another.
- Place in a shaded area and keep the substratum just cool.
- The rooting should take place before winter. The seedlings will be repaired in a cold greenhouse and then transferred to larger single pots in spring (or put directly in the house)

Pot cultivation

As we have said, hydrangeas also adapt to life in a container. To always have them beautiful it is essential to place them immediately in a large and deep vase: this will help us to always maintain the roots in a fresh environment and stimulate growth.
It is very important to create a good gravel or expanded clay-based drainage layer on the bottom. The ideal compote for this use is obtained by mixing about 50% of peat, 30% of sand and 20% of forest soil. It is also good to incorporate a good quantity of very seasoned flour manure.
On average, repotting should be done every two years, at the beginning of spring.
To avoid suffering the heat it is good to irrigate by immersion: we leave the vase immersed in a basin full of water for alternate days, for about 10 minutes, then drain it well.
In pot, more than in the ground (given the frequent watering and the consequent risk of salt accumulation) it is important to use rainwater or as much as possible limestone-free.
A thick mulching of the surface, based on coniferous bark, will help us to limit evaporation and contribute to maintaining the acid pH of the substrate.

Hydrangea: How to dry hydrangeas

The hydrangea corymbs are ideal for the creation of dry compositions, which will remain beautiful throughout the cold season. If possible, choose the most compact and bright pink ones, as it stays alive longer.
We proceed from August to September, before the autumn rains damage them. We eliminate all or most of the leaves and hang them upside down in a dry, warm and well-ventilated room. The more the desiccation will be rapid, the more the inflorescences will retain their original color and volume.
We can combine them with other flowers or, for example, with ears of wheat or barley. When we choose their location we keep in mind that the strong light will quickly fade them: we therefore prefer a slightly sheltered corner.
We also avoid vaporizing them with lacquer: it preserves the color of the flowers a little, but facilitates the accumulation of dust.
Watch the video
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