Dendrobium is a genus of epiphytic and terrestrial orchids that produce single to many-flowered racemes or dense clusters of showy flowers mainly in spring. Individual flowers are 1 to 3 inches across and often twisted or curled.
Dendrobium is a genus of about 900 species. Some are deciduous plants that flower on leafless growths made the previous season; others are warm-growing evergreen types that require a cool, dry rest period.
Dendrobiums like bright to direct light and warm temperatures. Where temperatures fall below 60°F (16°C), Dendrobiums should be grown as houseplants or in a greenhouse.
Get to Know Dendrobium
- Plant type: Epiphytic with some semiterrestrial orchids
- Growing zones and range: Zones 12-15
- Optimal growing temperature: day, 70° to 80°F (21° to 27°C). Night: evergreen, 60°F (16°C); deciduous, 55° to 60°F (13° to 16°C).
- Height and width: 6 to 24 inches (15-60cm) or more tall, some to 36 inches (90cm) tall and 6 to 18 inches (15-45cm) wide depending on the variety
- Foliage: Linear or lance-shaped ovate leaves usually flat; some leaves are thin, some are thick an leathery.
- Flowers: Single to many flowered racemes or panicles of showy white, rose-lilac, yellow, or oragne flowers appear from nodes along the stems; individual flowers 1 to 3 inches across, often twited or curled.
- Bloom time: Spring
- Uses: Houseplant, tropical garden
- Common name: Dendrobium
- Botanical name: Dendrobium
- Family name: Orchidaceae
- Origin: India, southeast Asia to New Guinea, Australia, and the Pacific Islands
Where to Plant Dendrobium
- Light: Indoors give Dendrobium bright light from southern exposure. Smaller plants do well under artificial light, needing 12 to 16 light hours daily. Good circulation of fresh air.
- Light: outdoors shade fDendrobium from direct summer sun at midday; can withstand several hours of direct sun in fall and winter.
- Soil: Grow potted Dendrobiums in Osmunda fiber or orchid bark mix.
- Grow Dendrobium epiphytically on a bark slab.
When to Plant Dendrobium
- Set Dendrobium outdoors any time of the year in tropical and subtropical regions.
Planting and Spacing Dendrobium
- Space Dendrobium 6 to 18 inches (15-45cm) wide depending on the variety.
How to Water and Feed Dendrobium
- Water: Let growing medium become almost dry between thorough waterings, except for D. phalaenopsis, which should be kept evenly moist. Mist frequently, especially on aerial roots. Humidity, 50% to 70%; evergreen plants require higher humidity than deciduous plants.
- Feeding: Feed deciduous species, monthly during active growth with all-purpose fertilizer. Feed evergreen species, twice a month during active growth with all-purpose fertilizer.
- Both deciduous and evergreen Dendrobiums follow the same cycle of maturation of growth, rest, and flowering, but require different culture.
- Evergreen types that require a rest period will not flower if watered during the rest time; deciduous types will rot if watered when leaf less and dormant.
- As growth of D. crepidatum matures, withhold fertilizer and water, misting just enough to keep canelike stems from shriveling. When blooms and new growth appear at same time in late spring, resume watering and feeding.
- D. densiflorum and D. farmeri require completely dry dormant period in order to bloom. When growth matures, withhold fertilizer and water, provide as much light as possible, and give cool (50°F/10°C) nights. When buds appear, resume watering, but then gradually reduce amount after flowering. Once active growth starts again, resume watering and feeding.
- D. nobile needs cold, dry dormancy to bloom; as growth matures, withhold water and fertilizer and provide cold (40° to 50°F/4° to 10°C) nights to initiate buds. Once buds appear, resume watering until flowering is finished, then gradually reduce amount until active growth has resumed.
Dendrobium Pests and Diseases
- Check Dendrobium for bacterial, fungal, and viral infections, mealybugs, scale, slugs, snails, whiteflies.
- Propage Dendrobium by division of pseudobulbs. Deciduous plants produce plantlets which may be removed and potted, or cuttings of canelike stems may be taken.
Dendrobium Varieties to Grow
- Dendrobium crepidatum. Deciduous plant which sheds its leaves before blooming; bears racemes of 2 to 3 white flowers with lavender and yellow markings; blooms in late winter or early spring.
- D densiflorum. Evergreen plant, produces pendent spikes of many flowers; blooms are pale to golden yellow; lip is yellow to orange, with slightly hairy texture; blooms in spring.
- D. fameri. Evergreen plant; produces many flowers borne on a drooping spike, colored soft pink or white; lip is golden yellow, slightly hairy and tipped with pink; flowers appear in spring or early summer.
- D. nobile. Deciduous plant; blooms appear on year-old, leafless canes; flowers are white with rosy tips in clusters of 2 or 3; white lip has pink rim and dark purple throat; flowers from spring to summer.
- D. phalaenopsis. Evergreen plant; grows to 36 inches (91 cm) and bears 5 to 15 flowers on long, arching sprays; blooms range from pink to white to red; lip is deep red with purple throat; flowers appear from spring to summer.