James Burghardt
Family
Orchidaceae
Botanical Name
Dendrobium
Plant Common Name
Dendrobium, Sentinel Orchid
General Description
Orchids in the genus Dendrobium are a large group numbering over 1200 species, and there are literally thousands of cultivated hybrid forms, called "grexes.” In fact, this is the largest of all orchid genera.
These showy flowering plants inhabit a wide range of habitats and elevations in tropical locations across the Eastern Hemisphere. Most are epiphytic, meaning they grow on other plants (usually trees) rather than being anchored in the soil. They have long, fleshy, bulbous bases called “pseudobulbs” that support oval, leathery, green leaves, which can be evergreen or deciduous. Long and slender or short and thick flower stems emerge from the pseudobulbs and support multiple flowers in various arrangements. The intricate blossoms come in a wide array of shapes sizes and colors and some are fragrant (often the deciduous species). Their flowers are generally long-lasting, which is why many are grown and sold for the cutflower industry, and can rebloom after a several-month resting period, though bloom time, length and frequency is species/grex dependent.
There are four major types of Dendrobium orchid that are defined by parentage and suites of physical and cultural factors. These include spatulata (antelope) types, phalaenopsis types, kingianum types and nobile types. The antelope-types are large, often evergreen, summer-blooming and have distinctive flowers with two erect petals resembling horns or antlers. The phalaenopsis types are often evergreen, have elongated pseudobulbs, tend to be fall-blooming and have long, terminal stems covered with sprays of brightly colored butterfly-like flowers. The kingianum types are spring-flowering and have strongly scented flowers and long leaves, and the nobile types are defined by colorful clusters of large flowers that are fragrant and often winter and spring-blooming.
Overall, these orchids appreciate very bright indirect light, good air circulation, high humidity and fast draining soilless potting media around their fleshy roots. They need more warmth, water and fertilization in the spring and summer, and drier, cooler weather in the winter to help induce blooming.
In tropical regions, they can be grown outdoors in trees or shade houses in all but the driest regions. They make great houseplants in temperate zones if provided with the correct cultural conditions.
