Orchids Plant Care

Epiphyte Orchid Plants

The cultivated orchids that excite the greatest interest are the epiphytes. These are “air plants,” which occur mostly in the tropical and subtropical rain forests and areas close to the equator.

Although they literally grow on trees, these orchids are not parasites; like bromeliads, they use the trees simply to gain a position that enjoys better light and air. Epiphytes such as vandas, which have long, freely suspended aerial roots, can exist only where temperatures are sufficiently high to prevent their exposed aerial roots from freezing.

Many epiphytic orchids, like the odontoglossums and miltoniopsis (pansy orchids) whose natural home is in the Andes mountain range of South America, grow at high altitudes. Here they can be found at up to 6,500 feet (2,000 meters), where the air is crisp and cool and the night often frosty. In cultivation, such exposure would greatly damage the plants, but in the rarefied air at high altitudes they come to no harm. The orchids produce their growth during the monsoons, and it is completed as the dry season approaches. Then the plants rest, or become dormant, a state that may last for anything from a few weeks to several months. Some, like the lycastes from Central America, will lose part or all of their foliage, flowering and making new growth (which they do simultaneously) only when the rains start up again.

The tropical and subtropical orchids that are the subject of these articles are mostly modern hybrids mainly derived from epiphytes growing in the wild in the tropical rain forests. Many of these epiphytes have evolved over thousands of years, experiencing little disturbance in an unchanging environment. In a rain forest, one large mature tree carrying a multitude or orchids can be likened to an apartment block in which every floor up to roof level is occupied. In an Asian rain forest, where the tree first forks, the trunk will hold large clumps of orchids such as cymbidiums and coelogynes, while in Central and South America there will be cattleyas and laelias. Toward the higher, thinner branches are smaller species, which may include odontoglossums, oncidiums, and masdevallias in South America, and bulbophyllums in Southeast Asia. The “penthouse” or canopy of the tree will be occupied by the smallest “twig” epiphytes, tiny miniatures too numerous to name, living life on the edge. All these orchids will receive varying amounts of dappled sunlight and shade from the trees, and moisture from the mists and rains that sweep in during the monsoon season.

Check out my part two article, Lithophytes Orchid Plants for more information on natural occurring orchid species.

May 31, 2007 comment TrackBack-URI