- On this page we will talk about:
- other articles:
Rhododendrons belong to the Rhododendron genus, which includes various species of shrubs, including the so-called Azaleas; the name derives from the Greek, and means rose tree, and well represents the appearance of these shrubs, which produce splendid spring blooms. The species, as we said, are very numerous, widespread in Europe, Asia and North America; in Italy we find few endemic species, mostly distributed in mountain areas, fresh and sunny; remember the Ferruginous rhododendron, which produces large pink spots during the summer in the alpine areas. Among all the species contained in the Rhododendron genus, what are commonly called rhododendrons are generally the evergreen species; these are shrubs of various sizes, from 30-40 cm, up to a few meters high, with shiny and persistent leaves, of a beautiful dark green color, which produce large bell-shaped flowers in late spring, gathered in splendid bouquets at the apex of the branches. In the garden we grow mostly hybrids, mainly derived from Asian species; the colors of the flowers are generally in shades of pink, often with streaks in contrasting shades; however, there are hundreds of hybrids, even with purple or blood red flowers.
The rhododendron genus belongs to the large family of herbaceous plants; these plants are acidophilic, that is, they need a specific soil to be able to vegetate at best. So we will plant ours rhododendron in a specific soil for acidophilic plants, possibly free of calcium, and consisting of peat and leaf compost. To favor a harmonious development of the rhododendron, and to avoid the most common diseases, it is essential that the soil in which it grows remains acid: unfortunately, watering with excessively calcareous water, and the proximity to soils rich in limestone, often cause the soil to become less acidic , compromising the development of our plants. Generally, this problem is remedied by watering the plants with rainwater, and by soiling the soil with fresh peat every year, so as to keep the pH low. In areas where the soil is very calcareous it is not advisable to grow rhododendrons in open ground, it is preferable to place them in pots, so that they can periodically replace all the soil in which the plant has its roots.
It is easy to notice when the soil is no longer acidic, because acidophilic plants grown in an excessively calcareous soil tend not to be able to absorb the iron dissolved in the substrate; the foliage gradually tends to lighten in color, until it becomes apple green, the flowers tend to decrease in number, and the plant takes on a sickly appearance, barely developing. To avoid these ailments, all gathered under the name of ferric chlorosis, we can first of all try to prevent the acidic soil from becoming basic, also we can also periodically supply greening fertilizer, which helps the plant to absorb all the mineral salts from the soil it needs.