Dendrobium

Dendrobium is a large genus of about 1800 diverse tropical orchid species in the Orchidaceae family. They are native to tropical areas of Asia down to New Zealand. Many of the plants in this genus are epiphytic (having roots that creep over the surface of trees) or lithophytic (having roots that creep over rock), . While species vary in form and size, most have elongated, cane-like pseudobulbs from which the leaves and inflorescences emerge. The flowers are bright, showy, and fragrant and come in a range of colors including white, orange, yellow, purple, pink, brown, and green. Many of the species in this genus will have a growth phase followed by a dormant phase over the course of a year. The genus name comes from the Greek words dendron meaning a tree and bios meaning life.

These plants grow best in bright, indirect light, idealy a west or south-facing window. A partially shaded site providing 2,000 to 5,000 fc light intensity should be sufficient (full, direct sunlight is approximately 10,000 fc by comparison). They prefer high humidity, around 60%, and need consistently moist soil.  Allow the soil to only halfway dry out between waterings, but never fully dry. Because these plants have small root systems, they MUST be planted in the smallest pot that fits and clay pots work well for maintaining good soil drainage. The genus includes deciduous species that lose their leaves during the dry season in nature. For these species, you should withhold water in the late fall and early winter to mimic natural conditions and stimulate blooming. The genus also includes hot, intermediate and cool-growing species, so consider temperature requirements to optimize growth and flowering. Most species can be grown in a bark-based medium containing horticultural charcoal. Feed weekly during the growing season after first watering thoroughly with tepid water. Use a commercial fertilizer diluted in water to half strength. 

Quick ID:

• Narrow pseudobulbs that are segmented (cane-like)
• Racemes of flowers without a sheath
• Spurs at the back of flowers

Diseases, Insect Pests, and Other Plant Problems:

These plants have few problems. They are generally not affected by pests, but watch for mealybugs. Insufficient light results in non-blooming.

VIDEO Created by Laura Barth for "Houseplants, Succulents, and Cacti", a plant identification course offered in partnership with Longwood Gardens.