A Detailed Guide to the Cultivation and Management of Dendrobium Orchids
Overview
Dendrobium (Dendrobium nobile), also known as the dendrobium orchid, is a plant of the genus Dendrobium in the orchid family. It is one of the orchid family plants recorded earliest in ancient Chinese literature. Because of its beautiful flower shapes and postures, brilliant colors, wide variety and long flowering period, it is deeply loved and valued by people in many countries and occupies an important position in the international flower market. Today it is widely cultivated in many countries around the world, especially in Southeast Asia. Among them, Thailand has the largest production, with an annual output of 3,600 tons of dendrobium orchids in 1993; in 1994 it exported 62.9 million stems to Italy, 14.25 million stems to the Netherlands and 11.7 million stems to Germany, and also exported to Japan and North America. In addition, Singapore, Malaysia and Taiwan, China also produce a certain amount, with the main export countries being the Netherlands, Germany, Italy, the United Kingdom, France and Japan. The Philippines mainly produces for its own domestic market. In Asia, Japan is the largest importer of dendrobium orchids; in 1993 the market@#@136@#@2.3 million pots, with sales of 28 million US dollars, ranking sixth in potted flower sales.
Large-scale production of dendrobium in China started relatively late, mainly beginning in the early 1990s. Although it started late, it developed very quickly. To date, there are production bases of a certain scale in Guangdong, Kunming, Fujian and other places, and in terms of potted flower and cut flower production they can basically meet the needs of the domestic market.
Morphological Characteristics and Varieties
Dendrobium is a perennial deciduous herb. The stems are clustered, upright, with the upper part slightly recurved and somewhat leaning, yellow-green, with groove lines. The leaves are nearly leathery and short and round. The raceme is large and white, with a light purple tip. It flowers during the leaf-shedding period.
Common cultivated varieties include K.B. No.1, with white flowers. Big Panda No.1, with red flowers. Pink Thamond, with pink flowers. Dynasty, with pink flowers. Thailand White, with white flowers. Sabin, with pink flowers. Sonia, with red flowers. White Tower, with white flowers. Madame Pompudoaur, with purplish-red flowers. Ceasai, with bicolored flowers. Recently, the Netherlands has also introduced a new dendrobium variety, Stardust Chiyoni, with yellow flowers, a multi-stem type, flowering in early spring.
Common ornamental species in the same genus include Dendrobium densiflorum, with golden-yellow flowers and an orange-yellow lip. Dendrobium nobile cv. Albiflorum, with white flowers and a dark brown center on the lip. Dendrobium superbum, with light purplish-red flowers and a purplish-red lip. Dendrobium secundum, with light purplish-red flowers and an orange-yellow lip. Dendrobium thyrsiflorum, with white flowers and a golden-yellow lip. Dendrobium phalaenopsis, with rose-red flowers.
Biological Characteristics
Dendrobium is native to China. It is distributed in South China, Southwest China and other regions. It often grows epiphytically on tree trunks or rocks in forests at an altitude of 480-1,700 m. It likes a warm, humid and semi-shady environment and is not cold-tolerant. The suitable growing temperature is 18-30°C; during the growing period 16-21°C is more suitable, during the dormant period 16-18°C, with nighttime temperatures of 10-13°C, and a temperature difference maintained at 10-15°C is best. Daytime temperatures above 30°C have little effect on dendrobium growth, and the winter temperature should not be lower than 10°C. Seedlings are easily frozen below 10°C. Dendrobium dislikes dryness and fears waterlogging, and especially from the time new buds begin to sprout until new roots form it needs sufficient water. However, if it is too humid, such as when encountering low temperatures, it can easily cause rot. When the weather is clear, dry and hot, in addition to watering, spray more water on the ground to maintain relatively high air humidity. Evergreen dendrobium types can maintain sufficient water in winter, but deciduous dendrobium types can be kept appropriately dry while maintaining relatively high air humidity. Dendrobium grows wild in forests, but in cultivation it is still rather light-loving; 50% shading in summer and autumn and 30% shading in winter and spring are suitable. If the light is too strong, the stems will swell and turn yellow, and the leaves will be yellow-green. However, sufficient sunlight results in good autumn flowering and a large number of flowers. The soil should use well-drained, airy crushed fern roots, sphagnum moss, charcoal crumbs, broken tile pieces, perlite, etc., mainly crushed fern roots and sphagnum moss.
Propagation Methods
Division, cuttings and tissue culture propagation are commonly used.
Division propagation: carry it out in spring together with repotting. Take the densely growing mother plant out of the pot, damaging the roots and leaves as little as possible, gently pull the orchid seedlings apart, and choose 3-4 plants to plant in a 15 cm pot, which is conducive to shaping and flowering.
Cutting propagation: choose pseudobulbs that have not flowered and are plump, cut them off from the base, then cut them into sections of 2-3 nodes each, insert them directly into peat moss or wrap the base of the cuttings with sphagnum moss, keep them moist, keep the room temperature at 18-22°C, and they can root 30-40 days after insertion. Once the roots are 3-5 cm long, pot them.
Tissue culture propagation: shoot tips and leaf tips are often used as explants; on MS medium supplemented with 2,4-D 0.15-0.5 mg/L and 6-benzylaminopurine 0.5 mg/L, the differentiation rate can reach about 1:10. The differentiated young shoots are transferred to MS medium containing activated charcoal and coconut milk (supplemented with 2,4-D and 6-benzylaminopurine at 0.1 mg/L each), where they can grow normally and form rootless seedlings. The seedlings are then transferred to MS medium containing indolebutyric acid 0.2-0.4 mg/L, which can induce rooting and form complete small plantlets with roots, stems and leaves.
Cultivation Management
Potted dendrobium needs a light, well-drained, airy substrate such as peat moss, fern roots, bark pieces and charcoal. At the same time, place more tile pieces or crushed brick crumbs at the bottom of the pot to facilitate root development. The cultivation site must have sufficient light, which is more favorable for dendrobium growth and flowering. During the growing period in spring and summer, water fully to speed up pseudobulb growth. After September, gradually reduce watering so that the pseudobulbs gradually mature, which can promote flowering. During the growing period, fertilize once every ten days; reduce fertilization in autumn; and completely stop fertilization when the pseudobulbs mature and during the winter dormant period. Dendrobium cultivated for more than 2-3 years becomes crowded, with roots filling the pot and the potting material already rotted, so it should be replaced in time. Whether evergreen or deciduous dendrobium, repot after flowering. When repotting, damage the roots as little as possible, otherwise the leaves will turn yellow and fall off when encountering low temperatures.
Pest and Disease Control
Black spot disease and viral disease are common; spray with 1,000 times dilution of 10% antibacterial agent 401 acetic acid solution. For pests, there is scale insect damage; spray with 2,000 times dilution of 40% omethoate emulsifiable concentrate to kill them.
Post-Production Handling
Dendrobium has beautiful flower postures and fresh, brilliant colors. As a potted plant it can be placed on a balcony or windowsill, or hung in a living room or study as a hanging basket, cascading in midair with a unique style. In Europe and America, dendrobium flowers are often used to make corsages, paired with baby's breath and asparagus fern, truly conveying a meaning of welcome. To date, they are widely used in large banquets and ribbon-cutting ceremonies for opening ceremonies, enjoying VIP treatment. In many countries, dendrobium is regarded as the flower of Father's Day on June 19 each year.