Azalea is not a genus in itself but is part of the rhododendron genus. This genus is divided into two groups: the rhododendrons, large evergreen or deciduous shrubs, and the azaleas, evergreen dwarf shrubs, with green leaves, or small and deciduous. Until a few years ago it was erroneously believed that they were two distinct species, but in reality both azaleas that rhododendrons are part of a single genus, that of Rhododendron in fact, which in turn is part of the family of ericaceous. They have a medium size and reach 40-90 cm in height; the thin stems, semi-woody, are densely branched, and give rise to round or elongated shrubs; the leaves are oval, dark green, rough and slightly leathery; in spring, before the leaves snack, they produce numerous trumpet flowers, gathered in bunches, at the apex of the branches, of pink, red or white color; there are numerous cultivars and hybrids, and in the last few years there are also on the market azaleas of lilac or blued color. Evergreen varieties slightly fear the cold, therefore they are grown as houseplants; the deciduous or semisempreverdi varieties are cultivated instead in the garden.
Azaleas generally like to be grown in a temperate climate. They certainly do not suffer damage in our area from -10 ° C to 20 ° C. However, it is possible to buy even more resistant varieties, the result of research and hybridization in recent years. If lower temperatures are reached in winter, it is advisable to remove the plant in a cold greenhouse or, if it is not possible, to place it near a wall to the south to protect it from at least strong winds. It can also be helpful to put insulation around the pot and cover the aerial part with a special sheet. In summer it is good to place it in the shade of large broad-leaved or coniferous trees, always maintaining high environmental humidity, much more important than that of the soil. For plants in the open ground it is always advisable to choose the right display. The more we live in a warm climate, the more indispensable it is to prefer a shady and cool area.Azalea soil
The substrate is certainly the element that is most important for successfully growing these plants. In fact, ericaceous plants need tendentially acid soil, with an optimal pH of around 5 / 5.5. A too high pH inhibits the absorption of nutrients and is the most frequent cause of chlorosis, which is manifested by the yellowing of the leaves. These plants need a soil rich in organic substances, well drained and without water stagnation, and should not be planted too deep, since they have a very superficial root system. They can also be grown in pots, remembering the greater demand for watering of potted plants than those placed in the open ground. Azaleas are acidophilic plants. They therefore need at least a sub-acid soil (the ideal is pH 5, 5-6).
The ideal soil is therefore what can be found under coniferous trees. To grow them in pots, you can therefore recover some of this soil from our garden or buy a suitable one. However, you must avoid preparations with a high percentage of peat. Rather it is better to choose a generic soil and mix needles, pine bark and possibly draining material (ideal is volcanic pumice or at most perlite).
To keep the soil cool and to avoid the pH change as much as possible, a good insulating layer can also be applied on the surface, again with the bark and pine needles. The root system does not develop in depth and therefore will require vessels that are wider than tall. On the bottom you should always prepare an excellent drainage layer of at least two centimeters. It can be composed of pumice or expanded clay. We avoid gravel that could release calcium carbonate. Always make sure the drain holes are free. Both in the ground and in the pot it is ideal to place the azalea in a slightly raised position with respect to the ground level, creating a mound. This will avoid the stagnation of water just where the plant is most delicate, that is in the area of the collar. However, at least until the plant has stabilized, more frequent irrigation interveners will occur.
In areas with a mild climate, the azaleas are placed in a sunny place; in areas with hot summers it is instead advisable to place the azaleas in a partially shaded or shaded place. The garden varieties do not fear the cold, even in the case of very cold temperatures. The shadow is undoubtedly preferable. We can evaluate different exposures if we live in the alpine or pre-alpine areas. Here it is particularly helped by lower temperatures, frequent rains and naturally higher atmospheric humidity. This does not mean that some varieties, especially deciduous ones, particularly love exposure in full sun and this will help them flourish profusely: the corollas, however, will last less. However they are specific characteristics of the cultivar and to know it you cannot do anything else but experiment. If the plant is in pot it is certainly worth the pain (especially if we live in a cool area) to try various exposures before deciding on the final one.
From March to October water the azalea regularly, avoiding however to soak the soil; during the winter months water sparingly, only in the case of prolonged periods of drought; the evergreen azaleas need to be watered throughout the year, keeping the soil slightly damp.
Fertilization is very important for a healthy and regular growth of the plant. After the plant has taken root, it is necessary to periodically fertilize with specific products for acidophilic plants; the yellowing of the leaves, due to chlorosis, is hindered by periodically providing an iron chelate-based amendment. Azaleas do not like to have constantly wet roots. This can cause rot and poor growth.
It is necessary to intervene more frequently after repotting or after planting, but let us make sure that the substrate is always slightly damp, but absolutely without excess.
It is much better to irrigate only once in an abundant manner, and then wait for the substrate to be completely dry than to distribute water constantly and without criterion.
If the days are particularly hot and dry, on the other hand, it is very useful to vaporize the leaves several times and (if we keep the plant on a pavement) wet the surrounding area so that the water evaporates gradually. It is excellent to place the plant on a saucer full of water and gravel, without it reaching the roots. It can also be useful to put around other broad-leaved plants that with their perspiration help to maintain a good environment for the azalea.
It should be remembered that, as these are generally calcifugal plants, it is better to use demineralized water (such as for irons) for irrigation and vaporization. It is also possible to collect and use rainwater.
To always have some beautiful azaleas to make the neighbor envious we give you little tips. Always remove the flowers at the end of the flowering, carefully removing the flower peduncle as well: this will prevent the plant from spending energy for the generation of seeds. Fertilize at least twice a month with iron sequestrene: the latter will help the absorption of nutrients with an evident greening of the leaves. Finally, remember that these plants suffer particularly watering during the hottest hours of the day, so it is good to wet them in the early hours of the morning or at night.
To have beautiful blooms it is good to intervene with specific fertilizers for acidophilic plants. Both granular slow release and liquid are good. Foliar fertilizers are also an excellent opportunity to combine with vaporisations. However, very light doses must be administered because these plants naturally live in rather poor soils and do not particularly like to be stimulated. We generally fertilize from February to mid-July, but don't go further. Our intervention could stimulate vegetative growth and the new branches, still herbaceous, could be irreparably damaged by winter frost.
Especially for potted specimens it is necessary to intervene with periodic pruning of the azalea to stimulate growth, maintain the shape and prevent them from becoming too large. The ideal is to intervene immediately after flowering. In fact, intervening too late can interfere with the emission of the branches that will bring flowers the following year. It is good to cut the outer branches more and try to make light inside the plant. Those that are crooked or damaged, on the other hand, can be eliminated at any time.
Loss of leaves
As we have said, there are deciduous azaleas and evergreen azaleas. The former usually lose their leaves by the end of summer. What is certain is that they lose them first if they live in a dry environment.
Even the evergreens lose their leaves. They do it in autumn and spring, but these have already been replaced by others grown in the summer and at the end of winter. If the leaves turn brown in the summer it is the signal that our azalea has a problem. Usually these are too many or too few irrigations, unsuitable soil or excessive fertilization.
Chlorosis of the leaves can be caused by various factors, but usually at the base there is too heavy soil and an abundance of calcium carbonate. As always the ideal is to avoid watering the plants with hard water and not to use cement pots. To remedy it is necessary to mix with the irrigation water of the iron sulphate. This lowers the pH of the soil, making the iron soluble again. If it is not sufficient, chelated iron can be administered either by irrigation or by leaf fertilization. It will in any case be useful to intervene as soon as possible by flaring the plant and replacing the substrate with a more suitable one and avoiding repeating the errors.
Life of azaleas
These are very long-lived plants. If treated in the right way they can live even more than 100 years. This is why they are also widely used for bonsai production.
Unfortunately it is not possible to give a precise indication of their flowering period. There are many varieties, cultivars and hybrids and can flower from the beginning of March to late October, depending on the climate in which we live. The advice is, if we have specific needs, to turn to specialized retailers who can direct us towards a specimen that meets our needs in terms of size, flowering, resistance and color of the buds.
How to treat florists' azaleas
Most of the azaleas that we have in our homes in pots come from purchases from florists. They are in fact considered excellent pot plants since they are quite simple to force and, in addition to having an excellent visual impact, they can be available all year round. What is really difficult, however, is to be able to make them survive and return to the following years.
First of all it would be important to be able to identify it to understand whether or not it is a rustic specimen. As soon as you get home it is important to remove the wrapping paper and, if the ground is dry, irrigate it thoroughly. A great method is to put it in a basin full of water and wait until no more air bubbles are produced. At that point you can take it out and let it drain for a long time. This operation must be carried out once a week. In any case, the soil must not remain moist for more than two hours each time. It must then be placed in the coolest area of the house, possibly where there is high environmental humidity. The bathroom could be a good solution as long as it is not too hot. In winter it can be moved to an unheated room. Generally even 5 or 6 ° C is not a problem. From spring to autumn it must be fertilized monthly with a low-nitrogen and high-phosphorus product. This stimulates rooting and bud production. Instead, excessive growth of leaves and branches should be avoided. It is necessary to check the roots every 6 months, extracting the ground bread: if we see that there are many and tangled on the bottom, we must intervene by cutting them. The plant must then be inserted in a slightly larger vessel than the previous one.
Variety of azalea
The name azalea is rather generic and within this label, the true fans of these acidophilic plants know all the main varieties. A first difference is made between flat azaleas and garden azaleas. A further more precise difference can then be made between the different varieties and cultivars of azalea.
The azalea mollis is a type of azalea very much appreciated because of its intense colors ranging from yellow, to red to pink, crossing all the shades of this color. Mollis have large funnel-shaped flowers but do not give a particularly fragrant bloom. One of the most interesting aspects of the azalea mollis and its flowers is the fact that this plant blooms when the leaves are not yet present and therefore the color effect is particularly intense.
The azaleas of Jinfo Mountain
For gardeners and more travelers, here is a place where azaleas are a corollary to a unique view and environment, so particular as to be identified as a World Heritage Site by UNESCO.
We are in China and more precisely on Jinfo Mountain, or Jinfo Shan, a 2238 meter high mountain that represents the highest peak of the Dalou mountains in the Chongqing district. This peak, from the name that means "mountain of the golden Buddha", in addition to offering incredibly beautiful views, is also an area in which the azaleas are widespread. In fact, between April and May, when these plants bloom, the mountain is filled with pink, white and red patches, creating an incredible chromatic effect.
Azalea in winter
The azalea is a plant that tolerates the cold winter climate of most of the areas of our country, including the main cities of northern Italy and the Po Valley. On the hills and in the colder alpine valleys, the winter frost and especially the late frosts can cause serious problems of survival to the azalea.
In these areas it will therefore be advisable to cover the azalea plants with a cloth during the coldest periods of the year.
In addition to this trick, we must remember to give a little to drink to the evergreen azaleas even in winter, obviously taking care to do it away from the less cold periods of winter to avoid damage to the plants due to frost. The evergreen plants in fact maintain a minimum of vegetative activity even during the winter period and in the absence of rain, when the soil becomes too dry, there can be serious problems for the plants planted outdoors.
Azaleas at home
The cultivation of azaleas in the home must take into account the factors that diversify the domestic environment from the external one, ie the temperature difference, the difference in humidity and the difference in light.
In the apartment and at home the temperature is more constant than outside and in winter it is certainly more suited to the vegetation of azaleas. However you have to be very careful not to expose the azaleas grown at home to excessive changes in temperature or too cold currents. Before taking the azalea outside then you will have to check that the temperature changes are not too accentuated to avoid dangerous frosts, so when choosing the position of the plants inside our house you will have to be careful not to put the azaleas in areas too exposed to cold currents or too close to outside doors and windows and which are often opened to ventilate the premises.
Light is another very important aspect to take into consideration and in particular in this regard it will be necessary to place the azalea plant in a place with sufficient lighting, therefore near a light source such as a glass door or a window.
Finally, with regard to humidity, the climate in the home tends to always be very dry and great care should be taken not to send the plant under water stress conditions, checking the soil humidity from time to time and eventually providing with the waterings.
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