Rhododendron

The genus Rhododendron includes up to 600 species, including azaleas, which until recently belonged to a separate genus. Azaleas are usually called deciduous varieties and hybrids of the Indian rhododendron species (R. indicum) with small leaves, many small twigs and beautiful inflorescence caps. Other rhododendrons are evergreen shrubs with powerful shoots and large dense leathery leaves of dark green color. Some species grow up to 6 m. These plants are distributed mainly in temperate and subtropical zones in cool and partially shaded areas.

The genus Rhododendron includes up to 600 species, including azaleas, which until recently belonged to a separate genus. Azaleas are usually called deciduous varieties and hybrids of the Indian rhododendron species (R. indicum) with small leaves, many small twigs and beautiful inflorescence caps. Other rhododendrons are evergreen shrubs with powerful shoots and large dense leathery leaves of dark green color.

Some species grow up to 6 m. These plants are distributed mainly in temperate and subtropical zones in cool and partially shaded areas.

Cultivation

Rhododendrons grow on acidic soil, so you need organic-rich soils, which include peat, pine needles,leaf humus, and turf. Only the so-called Indian azaleas can be grown in pots, and easily. Other species are planted on a permanent landing site away from the winds and scorching sun. In spring and autumn, it is transplanted from the pot in which it was purchased to open ground; during this operation, it is recommended to add white peat, which acidifies the soil. When growing in containers for better results humus is filled with complex fertilizer in the amount of 2-3 kg/m3. When planted on a permanent planting site, the soil is filled with mineral and organic fertilizers. It is better not to cultivate rhododendrons where it is impossible to provide plants with water in large quantities, strong winds or calcareous soils prevail. Applying liquid fertilizer in spring and autumn helps the plant to grow stronger and promotes abundant flowering.

Location

Rhododendrons don't like direct sunlight. The ideal place for harmonious growth is under large trees; here they receive diffused light that does not burn the flowers and leaves.

Temperature

All rhododendrons are resistant and tolerate even sub-zero temperatures; moreover, in winter they can not withstand temperature increases above 15 °C.

Watering

Humidity is one of the determining growth factors for rhododendrons, and the soil should never dry out. Therefore, it is necessary to water more often, first of all young plants, and necessarily - in the summer. In addition, it is necessary to moisten the foliage.

Care

Young plants are carefully pinched to promote more even branching. Remove dry and ugly parts of old branches, in grafted plants-bloating developing on rootstocks (so-called tops). At the end of flowering, pruning is carried out, but it should always be remembered that the rhododendron does not like excessive interference.: it can lead to the fact that the plant will not bloom at all for several years.

Reproduction

The most common method of propagation of rhododendron is by apical cuttings, which are taken from the tops; the time of cuttings depends on the species and variety. Usually cuttings are cut in July, but, for example, in Rhododendron catawibiens, it is better to take them in late August or early September. Usually, tender cuttings take root better than too strong ones, so a couple of months before cutting, it is recommended to remove the apical point of the shoot in order to provoke the development of lateral ones. By the way, the best cuttings are obtained from young plants. It can also be propagated by seeds and grafts.

The most common method of propagation of rhododendron is by apical cuttings, which are taken from the tops; the time of cuttings depends on the species and variety. Usually cuttings are cut in July, but, for example, in Rhododendron catawibiens, it is better to take them in late August or early September.

Usually, tender cuttings take root better than too strong ones, so a couple of months before cutting, it is recommended to remove the apical point of the shoot in order to provoke the development of lateral ones. By the way, the best cuttings are obtained from young plants.

It can also be propagated by seeds and grafts.

Diseases

The most common pests of this plant are nematodes, worms, aphids, whiteflies. They get rid of them with the help of insecticidal preparations Rhododendron are affected by late blight: Phytophthora cinnamonmii provokes yellowing of foliage and destruction of roots, after which the plant dies; Phytophthora cactorum causes browning and falling of leaves, stems and drying out. In both cases, after removing the diseased parts, the plant should be treated with special preparations-fungicides. Honeydew (Armillaria mellea) can settle on the roots. In this case, the plant will have to be discarded, as well as the infected land.

The most common pests of this plant are nematodes, worms, aphids, whiteflies. They get rid of them with the help of insecticidal preparations Rhododendron are affected by late blight: Phytophthora cinnamonmii provokes yellowing of foliage and destruction of roots, after which the plant dies; Phytophthora cactorum causes browning and falling of leaves, stems and drying out. In both cases, after removing the diseased parts, the plant should be treated with special preparations-fungicides.

Honeydew (Armillaria mellea) can settle on the roots. In this case, the plant will have to be discarded, as well as the infected land.

Acquisition

The preferred time to purchase rhododendrons and azaleas is early spring. You should choose plants with strong buds (the flowers have not opened, but their color is already visible) and whole leaves.

Rhododendron of pontus Rhododendron ponticum (Rhododendron ponticum) originated from Europe and Asia Minor. This is an evergreen ground species, reaching 6 m in height, the crown grows to 10 m in diameter. The leaves are glossy, dark green, 9-12 cm long. Purple funnel-shaped flowers with a diameter of about 5 cm are collected in multi-flowered brushes. This species is particularly well suited as a rootstock for breeding hybrids. Katawba rhododendron Rhododendron catawibiens is an evergreen shrub native to North America, reaching 4 m in height and diameter. Oblong glossy leathery leaves have a dark green color. Lilac-purple funnel-shaped flowers (5-6 cm in diameter), the mouth of which is covered with green spots, are collected in inflorescences of 15-20 pieces. This species is widely used in creating new hybrids and varieties. Yakushimanum rhododendron The Yakushimanum rhododendron (Rhododendron yakushimanum) originated from Japan. It is an evergreen dwarf shrub (grows up to 60 cm in height and grows 90 cm apart) with oblong-lanceolate leathery dark green leaves. Collected in dense dome-shaped inflorescences, the flowers are pink in the buds, open-lighten, become almost white. Hybrids Numerous rhododendron hybrids are grouped into the following groups: 1. evergreen rhododendrons derived from Asian species, usually with flowers 3-8 cm in diameter; 2. ground evergreen rhododendrons obtained from European, American and Asian species; height and diameter 3-5 m; funnel-shaped flowers with a diameter of 5-8 cm; 3. deciduous rhododendrons, which are grown in greenhouses, and in areas with mild climates - in gardens; fragrant flowers have a bell shape; 4. azalio-dendrons-hybrids of Indian azalea and related rhododendron species; 5. western hybrids obtained by crossing R. occidantale and Indian azalea 'Soft'.

Rhododendron of pontus

Rhododendron ponticum (Rhododendron ponticum) originated from Europe and Asia Minor. This is an evergreen ground species, reaching 6 m in height, the crown grows to 10 m in diameter. The leaves are glossy, dark green, 9-12 cm long. Purple funnel-shaped flowers with a diameter of about 5 cm are collected in multi-flowered brushes.

This species is particularly well suited as a rootstock for breeding hybrids.

Katawba rhododendron

Rhododendron catawibiens is an evergreen shrub native to North America, reaching 4 m in height and diameter. Oblong glossy leathery leaves have a dark green color. Lilac-purple funnel-shaped flowers (5-6 cm in diameter), the mouth of which is covered with green spots, are collected in inflorescences of 15-20 pieces.

This species is widely used in creating new hybrids and varieties.

Yakushimanum rhododendron

The Yakushimanum rhododendron (Rhododendron yakushimanum) originated from Japan. It is an evergreen dwarf shrub (grows up to 60 cm in height and grows 90 cm apart) with oblong-lanceolate leathery dark green leaves. Collected in dense dome-shaped inflorescences, the flowers are pink in the buds, open-lighten, become almost white.

Hybrids

Numerous rhododendron hybrids are grouped into the following groups:

1. evergreen rhododendrons derived from Asian species, usually with flowers 3-8 cm in diameter;

2. ground evergreen rhododendrons obtained from European, American and Asian species; height and diameter 3-5 m; funnel-shaped flowers with a diameter of 5-8 cm;

3. deciduous rhododendrons, which are grown in greenhouses, and in areas with mild climates - in gardens; fragrant flowers have a bell shape;

4. azalio-dendrons-hybrids of Indian azalea and related rhododendron species;

5. western hybrids obtained by crossing R. occidantale and Indian azalea 'Soft'.