Although there are thousands of species and tens of thousands of different hybrids of the orchid flower, only two different types of orchids exist.  Orchids that grow on the ground are called terrestrial orchids, while epiphytic orchids grow on the bark of living trees, on rocks and on poles, and they can grow on many other unlikely surfaces too.

The term "epiphyte" does not only refer to orchids, but refers to any living plant that has its root system above the ground.

Many people love the thousands of terrestrial orchid species.  Like most other plants, terrestrial orchids have roots that grow beneath the ground or the surface of the soil in a pot.

As it is with most living things, however, there are exceptions to the rules, and orchids are no exception.  Some terrestrial orchids are termed "semi-terrestrial," meaning that they have underground roots and aerial roots too.

One of the first species of orchid to be cultivated was the Cymbidium orchid.  This is a terrestrial plant with forty species and many thousands of hybrids.  A very adaptable type, a Cymbidium orchid can grow on rocks and trees as well as in the ground.  It's very happy nestled in a patch of rotted wood or a pile of decaying leaves.

Cymbidiums originated in the far East, and can now be found from Japan to Southeast Asia.  They've traveled as far as Australia, too.  Since they are so adaptable, they are very forgiving with beginning horticulturists, and this has made them very popular.  As a bonus, they provide a wonderful, rich array of gorgeous flowers every year.

The best known epiphytic orchid (having its roots not in the ground) is the Dendrobium orchid.  They are a bit more particular than Cymbidium orchids, requiring a bit more time and attention, but they are fairly easy to grow.  Generally, they don't flower as easily as Cymbidiums.

There are more than 1000 species of Dendrobium orchids, and they can still be found in their natural habitats in Australia, Polynesia, South East Asia and northern India.

Having originated in tropical areas, Dendrobiums love warmth and humidity.  Therefore they should be kept reasonably moist.

Another popular epiphyte orchid is the Phalaenopsis orchid.  These have very long-lasting flowers, and they are easy to grow, too.  Because of their exotic look and their variety of colors and stripes as well as basic white, Phalaenopsis orchids are a favorite at weddings.

Alhough epiphytic orchids attach themselves to structures like trees, they don't feed off the tree.  An epiphytic orchid will wrap its fleshy roots around the nooks and crannies on the bark of its host tree.  As organic matter slips down the trunk of the tree, it can become caught in the orchid's roots, and be used as nourishment for the orchid.

The roots of epiphytic orchids also help the plant survive through wet and dry periods.  The tough, stringy core of the root is surrounded by a spongy off-white covering that absorbs water easily.  When it rains, this cover soaks up water.  When it is completely saturated, it turns light green.

Rather than releasing the water into the plant too soon, thereby most likely killing it, the orchid's roots hold the moisture.  The roots release it to the flower tissues gradually, as needed.

There are also some species of epiphytic orchids that cling to rocks.  Since they hang from trees, rocks, or other objects, the epiphytes thrive in the filtered light and they are always in open, airy situations.

By learning what helps orchids thrive and making just a few tweaks to your houseplant care routine, you will be able to grow these remarkable flowers at home and keep them healthy for years to come.