The pieris (once grouped in the genus Andromeda) are evergreen shrubs, of medium or small size, widespread especially in the mountainous areas of central and eastern Asia; some botanical species are also present in the American continent, but in European nurseries there are mainly hybrids and species originating in Asia, in particular Pieris japonica and its hybrids. It has a beautiful dark green, lanceolate, coriaceous, spiral-shaped foliage; the leaves of the shoots are in many species in contrasting color, in particular red or purple, and become green with the passing of days. The flowers are gathered in terminal and pendulous racemes, have tiny dimensions and are bell-shaped, white in color; typically bloom in late winter or early spring. The flower buds are already prepared by the plants during the summer, and therefore remain on the plant for several weeks before blossoming, often remaining light green. There are dozens of hybrids, with pink flowers or those with dark veins, or with young leaves tinged with fiery red. The flowers are followed by tiny fruits, semi-woody capsules that contain seeds, usually fertile. Besides these there are also dwarf varieties; a pieris an adult, who is a few years old, can easily reach two or three meters in height; dwarf varieties, on the other hand, remain below the meter, approximately.
Pieris speciesPieris japonica
It is one of the most widespread species as an ornamental plant, and also that of which there are several hybrid varieties; the pieris japonica, as the name suggests, originates from Japan and China. These pieris are medium-sized shrubs, very slow growing, which remain dense and thick even without pruning of any kind; the foliage is dark green, in the buds it is bronze. The varieties typically have very showy bud foliage, cherry red, orange, or even intense yellow, which makes the shrubs very decorative. The flowers are white, they bloom in early summer, in long pendulous racemes, often covering the entire shrub in large quantities.
Species native to the United States, it has a decidedly less compact appearance and bearing than the Japanese cook; the stems are thin, well branched, and bear oval leaves, medium green, evergreen, larger and lighter than those of pieris japonica, and without the typical contrasting color of the shoots. The flowers bloom at the apex of the stems, in erect panicles, which then come out conspicuously from the whole of the shrub, are very fragrant. Very robust and vigorous plant, it does not show the elegant and delicate aspect of other pieris, more widespread in cultivation.
Species widespread in nature in Central Asia, in Himalayan areas; it has slightly larger dimensions than pieris japonica, especially as regards the leaves, which although maintaining a similar shape, are decidedly larger, with a length that can exceed 15 sc; the general appearance of the shrub is very similar, with rounded shape, dense branches and slow growth. The young spring leaves of Pieris formosa are of a showy cherry color, which turns to orange and yellow before reaching the true de typical of mature leaves. The flowers are white, bell-shaped, delicately scented, they bloom in spring, when the shrub produces the most striking foliage.
The pieris belong to the family of the ericaceous, they are therefore acidophilous plants, which need fresh soil and acid ph, devoid of limestone; they are then cultivated in appropriate soil, avoiding watering them with strongly calcareous water. In areas with alkaline soil it is usually preferable to grow the pieris in pots, so as to better control the soil around the roots; or a large planting hole is prepared, which must be filled with peat and soil for acidophilic plants; if we live in an area with strongly calcareous water, the soil around the pieris will be replaced periodically, or we risk that over the years it will become excessively poor in bio-available iron, causing ferric chlorosis, or an irreparable yellowing of the foliage. The pieris are plants of the undergrowth, used in nature to live in areas with cold internal winter and cool summers; in Italy they find a place in partially shaded flowerbeds, sheltered from the direct sun during the hottest hours of the day. They can withstand direct sun, but in summer it would cause excessively high temperatures and very dry air. The pieris can endure short dry periods, but they prefer a cool and humid climate, they must therefore be watered regularly, from March to September, avoiding leaving the soil for a long time; however, we also avoid excesses, and therefore the soil should be dry before watering again, and we guarantee our plants a fertile, deep and very well drained soil, so that excess water can slip away quickly. Throughout the growing season we supply n fertilizer for acid-flowering plants, every 12-15 days; we can use the same fertilizer that we supply to azaleas or hydrangeas. They are very decorative plants, without great needs, in fact the development is very slow, and therefore it is usually not necessary to prune the pieris; if it should be necessary, we shorten the racemes of withered flowers, and remember to avoid autumn pruning, as they would certainly remove most of the future flowers.
Pests and diseases
The pieris are not much attacked by animal pests, as aphids and scale insects do not like the cool and humid climate in which the plant is cultivated, and the same is true for loved ones; if therefore these insects should attack our pieris, it means that the plant is also not healthy, as it is cultivated in an excessively hot and dry place or without ventilation. More typically, pieris suffer from ferric chlorosis, a disease that attacks acidophilic plants when they are unable to absorb iron in the soil and synthesize chlorophyll; for this reason the leaves tend to become progressively yellow, and the plant visibly deteriorates. Against ferric chlorosis, the best cure is prevention, which is carried out by growing the plants in a ph acid medium, or periodically supplying a soothing fertilizer.
Another problem often found in pieris is due to an excessively heavy and always aging soil, which favors the development of rot, which can irreparably ruin the root system.
Pieris japonica: Multiply the pieris
The pieris produce many flowers, followed by small fruits that contain fertile seeds; these seeds can be harvested and sown immediately, when they are still "fresh"; they are sown in seed trays filled with peat and sand in equal parts, which must be kept moist and in a cool place sheltered from direct sunlight. Usually germination is not safe, therefore we tend to sow a large quantity of seeds, immediately thinning out the plants that sprout, to keep only the most vigorous and large ones. If we have taken the seeds from a pieris of a hybrid variety, we will not necessarily get young plants identical to the mother plant. For this reason it is usually preferable to propagate the pieris by cuttings, in late spring or in summer, by taking cuttings from branches that do not bear flowers; the cuttings must be at least 6-10 cm long, and must be stripped of most of the leaves, especially in the lower part; they immerse themselves in the rooting hormone, and then bury themselves in a compound of peat and sand, which must be kept moist for a long time, in a partially shaded place, until the cuttings have begun to sprout; at this point we will move them into individual containers, which will be tried in a sheltered place. Although the pieris are very cold-resistant plants, which can withstand temperatures close to -15 ° C, it would be advisable to keep the seedlings from seedlings and cuttings in a sheltered place for their first winter, in a cold greenhouse or on a terrace. A shelf against the walls of the house and not excessively exposed to the sun and weather can be enough to preserve the tiny plants without being ruined.
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