Azalea - Rhododendron

In areas with a mild climate, azaleas can be safely placed outdoors all year round. However, in areas subject to colder temperatures, they need to be protected, for example by placing them in a cold greenhouse, at least during periods of frost. During the summer, this species tolerates the high temperatures of the hottest days quite well, although it is always best to provide shelter from direct sunlight, otherwise the leaves take on a reddish color and lose much of their shine. Furthermore, in case of excessive sun exposure, there is a risk of dehydration and failure to assimilate fertilizer, resulting in spotting on the edges of the leaves, similar to that caused by fungi. It is important to keep in mind that Azaleas also benefit from a well-ventilated location. If you want to keep it indoors for a while to fully enjoy its spectacular flowering, you can do so, provided it is for a very limited period: a maximum of 4 days.

Azaleas do not like hard water: if this problem arises, it is best to use a descaling product such as those in the Bonsan range. As for how often to water, a distinction must be made depending on the season: during the growing season, until the end of July, watering should be very abundant, while after flowering, it should be more moderate. However, it is important never to let the soil dry out completely, even in winter (including the coldest months), as its thin fibrous roots dehydrate easily. Ensuring the right amount of water for azaleas is very important in order to avoid cultivation problems: overwatering leads to weak and long growth, with consequent leaf fall; under-watering causes stunted growth, with twisted, yellow leaves that will fall, along with the buds.

The best time for transplanting is immediately after flowering, because if done earlier, the plant would weaken at the expense of flower production. Young specimens should be transplanted every 2 years, while for more mature ones, every 3 or 4 years will suffice. Azaleas tolerate root pruning well, and after the operation they generally produce numerous capillary roots in a short time. Before transplanting, remove the soil from the top and bottom of the stump, paying particular attention to the central area under the tree trunk, where it is easy to find rotting roots and dry, compact soil. At this point, prune one-third of the roots, giving priority to the thickest ones. The cuts resulting from the operation should be treated with healing mastic. The optimal compound is kanuma.

Since these are fast-growing plants, it won't take long for them to develop good branching. Before flowering, the branches must be thinned out, pruning the shoots that grow directly upwards or downwards; in an already formed plant, even the strongest shoots must be cut. When the tree is about to flower, in order to avoid excessive stress on the tree, a selection of buds is made. Every 12-13 years, to reinvigorate the plant and obtain the best possible flowering, the Japanese recommend completely removing the main branches and starting the shaping process again. When pruning, care must be taken to prune the apex less than other parts of the tree, as this is the weakest area.

This is done to help stimulate the growth of new branches and keep the bonsai's foliage compact and well-structured. This practice consists of gently removing the tips of new shoots, which are still soft. It should be done throughout the growing season, from spring to summer, but not during flowering, as the flower buds could be damaged. The operation should be carried out regularly, every 2-3 weeks, when the new shoots are still young, and consists of removing about 2-4 leaves to stimulate denser growth and reduce overly long internodes, which could compromise the shape of the bonsai.

The best time to apply the wire is after flowering because, having pruned, the structure of the tree is more visible. Copper wire is the most suitable because it is stiffer than copper-coated aluminum wire and therefore provides a better hold, especially for thick branches. To achieve good results without taking any risks with this technique, it is important to bear in mind that azalea wood is very delicate and therefore young branches should not be wrapped. One tip to keep in mind when applying the wire is to cover it with florist's tape to avoid leaving marks on the bark. You should also take care to remove it as soon as it starts to cut into the bark. For thick, vigorous branches, it is better not to use wire to shape them, but rather tie rods and weights.

At the end of flowering, after pruning, apply Bonsan Stimulating Fertilizer combined with Bonsan Liquid Organic Fertilizer three times every 8-10 days. During other periods, use Bonsan Hanagokoro Solid Organic Fertilizer every 15-25 days, excluding July and August. Twice a year (in autumn and at the end of winter), apply Bonsan Hanagokoro Solid Organic Fertilizer. It is also advisable to apply Bonsan Mineral Curative Solution 6-8 times a year. To stimulate rooting, use Bonsan Organic Mineral Liquid Fertilizer with B vitamins instead of Bonsan Organic Liquid Fertilizer.

The diseases to which azaleas are most frequently susceptible are: scale insects, aphids, mites, red spider mites, and sooty mold. To prevent these pests from attacking the plant, simply follow the correct maintenance rules, especially with regard to exposure and watering. However, if they do appear, they can be easily eradicated by applying specific products. However, to avoid having to treat the plant once it has already been attacked, it is advisable to carry out appropriate preventive treatments periodically.