Rhododendron DAURICUM

Rhododendron DAURICUM - Dahurian rhododendron, Rhododendron dauricum, Dahurian azalea, Siberian bagulnik, Azalea ATROVIRENS.

Can be grown in bonsai style!

Rhododendron is a genus of woody plants in the heath family Ericaceae, comprising 1,096 accepted species distributed in temperate regions of the Northern Hemisphere, in the mountains of tropical Asia, and in northeastern Australia. In nature, representatives of the genus occur in mountain forests, on moist slopes, peat soils, rocky ledges, forest margins, and in subalpine shrub communities, where an acidic soil reaction and moderate moisture are usually maintained. Azaleas, previously separated into an independent subgenus, are also included in the genus.

The genus is characterized by evergreen, semi-evergreen, or deciduous shrubs and small trees with a shallow fibrous root system. The leaves are arranged alternately, often clustered closer to shoot tips, and can be leathery, elliptic, lanceolate, or obovate, with a smooth, pubescent, or lepidote surface depending on the group.

The flowers are usually large, funnelform, campanulate, or tubular, gathered in terminal inflorescences, colored in white, pink, purple, red, yellow, or lilac tones. After flowering, dry multi-seeded capsules that open by valves form, while the seeds are very small, dust-like or narrowly winged, adapted for wind dispersal.

Dahurian rhododendron is a deciduous or semi-evergreen shrub usually 0.5-2 m (1.6-6.6 ft) high with slender, densely branching shoots. The bark is grayish-brown, shoots are flexible, forming a loose but dense crown. The leaves are small, leathery, oblong, dark green above, paler beneath; part of the leaves may persist in winter and fall only in spring. The branches and foliage often have a resinous aroma.

Flowering occurs in early spring, often before the unfurling of new foliage. The flowers are large for the size of the shrub, funnelform, pink-lilac or purple-pink, arranged in clusters of several at shoot tips and creating a vivid effect against the backdrop of still "bare" branches. After flowering, dry capsules form in which numerous small seeds ripen.

Dahurian rhododendron is known as one of the earliest-flowering shrubs of the temperate zone and is frequently used in landscaping due to high winter hardiness and the ability to bloom before the full warm-up of spring. In cultivation, this species is perceived as one of the "northern" rhododendrons that retains ornamental appeal not only through flowering, but also thanks to a neat crown and compact growth.

Rhododendron seeds are very small, dust-like, light brown, ripening in dry oblong capsules that open by valves.

Sowing is carried out from late winter to spring or year-round in the presence of grow lights and a stable cool temperature. A sterile acidic substrate based on sifted peat, shredded peat moss, perlite, and a small amount of washed sand is used. Seeds are sown superficially, not covered with soil, but only lightly pressed against the moist surface, since light is needed for germination. The sowing is moistened from a spray bottle with a weak solution of growth stimulant - SUPERthrive, HB-101, Aminozol, Epin, or Zircon are used.

First seedlings usually appear in 10-14 days; the average germination period is 2-4 weeks, and the maximum possible period with cool maintenance and uneven seed germination reaches 6 weeks. After the appearance of the first leaves, the cover is opened gradually and the maintenance temperature is lowered to 8-12 °C (46-54 °F) - this reduces the risk of fungal diseases in seedlings. Watering of seedlings is conducted through the tray: the container is filled with water until the substrate is completely soaked, after which excess water is drained. Pricking out is carried out after the formation of 2-3 true leaves, very carefully, preserving the delicate roots and without burying the growing point. First flowering occurs in the 3rd-4th year after sowing.

© Greeniverse. All rights reserved.

For rhododendrons, bright indirect light or light partial shade is used, especially in regions with hot summers. Eastern and northeastern exposures are suitable, as well as locations beneath an open tree canopy where the plant is sheltered from direct midday sun. With a lack of light, flowering weakens, while in excess sun leaves suffer sunburn, especially in dry air and with root overheating.

During the period of active growth, a temperature of 16-24 °C (61-75 °F) is maintained; with sufficient air and soil humidity, a short-term increase to 28 °C (82 °F) is permissible. Overwintering is carried out in a cool, bright place at 2-10 °C (36-50 °F), for a container plant preferably without freezing of the root ball. The minimum depends on age and growing conditions, but in pot culture roots are protected from temperatures below -5 °C (23 °F), since container substrate freezes faster than open ground.

Watering is carried out regularly, with soft, slightly acidic water, without drying out the root ball and without stagnant water. The soil is maintained evenly moist, but not waterlogged, and excess water from the drip tray must be drained. Drying out causes wilting and drying of leaf margins, while prolonged overwatering leads to root rot. In hot weather, increasing air humidity and careful spraying of the crown in the morning or evening is beneficial. Loosening of the soil under the bushes is not performed due to the superficial location of roots.

For planting, an acidic, loose, moisture-retentive, and aerated substrate with a pH of about 4.5-5.5 is used, composed of peat moss, coniferous litter, bark, perlite, and a small amount of coarse sand. Drainage is laid at the bottom, but the mixture itself must not be alkaline or calcareous. Pots are chosen wide and not too deep, since the root system is superficial. Repotting is carried out carefully, usually once every 2-3 years, without disturbing the root ball.

Fertilizer is applied from April to July once every 3-4 weeks with a weak solution of acidic complete fertilizer for rhododendrons, azaleas, or ericaceous plants. In the second half of summer, nitrogen feedings are stopped so that shoots have time to mature. Pruning is carried out minimally after flowering: dried inflorescences, damaged branches, and weak shoots are removed, while hard pruning is applied only to old plants and is performed gradually.