The Dendrobium Orchid

Dendrobium orchids and their hybrids form the second largest group of orchids after the Bulbophyllum orchids. There is way over 1,500 species of Dendrobium orchids in this group and thousands more types of orchid hybrids in the Dendrobium orchid group; and they are well dispersed all over the world. Nowadays it is not uncommon to find a Dendrobium orchid growing in India, Japan, the Philippines, Malaysia, Papua New Guinea, the Polynesian Islands, Australia and New Zealand.

Dendrobium orchids and Dendrobium orchid hybrids are also cultivated in other areas and due to this widespread distribution it is hard to put them in a specific climatic category. Many Dendrobium orchids are tropical, some prefer intermediate conditions and others actually prefer cooler climates. The most common denominator in Dendrobium orchids is however the fact that they all prefer good light. As long as there is bright light Dendrobium orchids will be too happy in any climate.

Dendrobium orchid plants vary in size, some being smaller than a matchbox, others large, robust specimens measuring over 1 meter in length, I dare not say height. They are epiphytic by nature and require good light and ventilation. Some Dendrobium orchids are deciduous while others are evergreen. Some have pseudobulbs from long and thin to fat and succulent; and others have jointed stems resembling canes. Because of the complexity of this genus, some varieties may prove to be shy to flower. The Dendrobium orchid flower occurs in almost every imaginable color. The flower spikes can be over two feet tall with over twenty blooms on them. The flowers last for 6 to 8 weeks and they make excellent cut flowers. The blooms are all the colors of the rainbow – pinks, lavenders, reds, yellows, oranges and many mixed color combinations. Lavender or white flowers are borne in profusion on a well-grown plant and are long lasting. They are a prolific group in which offset plantlets are frequently produced on the cane. When each offset has produced several aerial roots, it can be cut from the parent plant and will frequently flower after one year of growth.

Temperature

The cool-growing orchids in the Dendrobium orchid group prefers temperatures ranging between 10 and 24° Celsius (that is between 50 and 75° Fahrenheit). The intermediate Dendrobium orchid prefers a temperature range of 14 to 26° Celsius (58 to 79° Fahrenheit), whereas the warm-growing Dendrobium orchid prefers 16 to 30° Celsius (52 to 86° Fahrenheit).

Light

Where the Dendrobium orchid you are cultivating is of the cool-growing, intermediate-growing or warm-climate growing orchids, they all prefer bright light.

Water and humidity

When the new growth begins in the spring, the Dendrobium orchid likes to have an increase in water and fertilizer. Culture during spring and summer is similar to the Phalaenopsis orchid, with reduced light, increased water, and good orchid fertilizer every two weeks (1 teaspoon per gallon of water soluble fertilizer). In the fall, cultural needs change drastically. Bright light, cooler temperatures and no fertilizer will help to initiate flower buds. Water normally so that the bulbs do not shrivel. Occasional misting on the foliage will help any moisture loss occurring during very warm days in tropical and sub-tropical climates. Buds will appear when the night temperatures are cooler and the growths have fully matured. This is usually in mid-winter.

Feeding

All Dendrobium orchids, including the Dendrobium orchid hybrids, need to be fed regularly.

Pests and Diseases

Which-ever medium is used, it must be open enough to maintain some air around the roots. The Dendrobium orchid cannot tolerate wet, soggy composts, which will inevitably damage and rot their wiry roots.

Potting mix and Repotting

Do not overpot the plants. They like to be root-bound and do well in relatively small pots. Clay pots suit them well, as does regular seedling bark mixture or osmunda. Some growers also use long-fibered sphagnum moss for these Dendrobium orchids.

Keikis or off-shoots may form on the stems, and these may be potted as new plants when they start to form roots. If plants produce all keikis and no blooms, too much fertilizer and temperatures too warm at night are usually to blame.

Cool-growing Dendrobium orchid species

In this group of Dendrobium orchids you will also find the miniature Dendrobium orchids that originate from areas like New Guinea. The specific Dendrobium orchid that comes to mind here is the Dendrobium cuthbertsonii. This Dendrobium orchid thrives in warm climates when conditions are cool. And they do equally well in tropical climates in controlled greenhouse conditions.

The flowers in the warm-growing Dendrobium orchid range come in many different shades: Yellow, orange, red, pink, bi-colored, and so much more. These small Dendrobium orchids in maturity only reach a height of abut 5 cm (that is 2 inches). They are best cultivated on tree ferns where they can also enjoy the benefits of an occasional cool cloud cover.

This particular Dendrobium orchid can be successfully cultivated in small pots, on slabs of osmunda or even rafts of tree ferns. You need to ensure to always give the Dendrobium orchid regular water. You also need to feed it on a regular basis with a weak solution of general orchid fertilizer. Always ensure that the Dendrobium orchid with its little bulbs is kept plump.

Intermediate-growing Dendrobium orchid species

Mentioning intermediate-growing orchids and Dendrobium orchids in one breath can never be complete without mentioning the stunning nobile Dendrobium orchid. The nobile Dendrobium orchid originates from the mountainous areas in Asia, more specific the Himalayas. Strange enough that the Dendrobium orchids were popularized in Hawaii and Japan. In Japan by the Yamamoto family to such an extent that the Dendrobium orchids are often referred to as the Yamamoto Dendrobium orchids.

These orchids are well known for their abundance of flowers in spring after they have been left to dry throughout the cool winter months. What is even stranger is that the old canes and old bulbs on Dendrobium orchids in this group can also produce flowers.

During the latter part of spring and throughout the whole of summer the Dendrobium orchid, especially the Yamamoto Dendrobium orchid has a growth spurt that is second to no other orchid. New growth emerges from the base of the plant and matures in no time. It thus does not take a rocket scientist to realize that during this growth spurt, the orchid plant needs constant watering and feeding to ensure that the canes or pseudobulbs are kept fat and succulent. Usually the stems are quite heavy and should be secured and supported.

During the fall, when temperatures begin to fall you should apply a high potash-based fertilizer and place the orchid plants in a dry part of your greenhouse if you are cultivating your orchids in a greenhouse. You will notice buds appearing from almost every node along the swollen canes. If you water the nobile Dendrobium orchids at this stage, it will commence its natural growth cycle and the little buds would develop into little plants with very few or even no flowers. Thus if you want the Dendrobium orchid to flower, you should refrain from watering the orchid plant at this stage. Wait until the orchid flowers open. Very important in cultivating nobile Dendrobium orchids is bright light which in turn will maximize orchid flower production.

After the orchid flowering period it is important to repot your Dendrobium orchid to ensure that your orchid plant will experience an active growth period. You may even have to remove old canes where necessary and lay them ion damp, washed river sand where, over the summer, the bulbs will develop new keikis that can be removed at the end of the growth season to be planted. Obviously you will then be cultivating orchid plants that will be identical to the parent plants, but what a great way to increase your collection.

Warmer-growing Dendrobium orchid species

In this group of Dendrobium orchids you will find the ‘antelope‘ and Phalaenopsis type of orchids. The antelope Dendrobium orchid flowers are erect and have spiraling petals whereas the Phalaenopsis Dendrobium orchid flowers are full and rounded in shape. And although the Phalaenopsis orchid and the Dendrobium orchid in this specific warmer-growing Dendrobium orchid look alike, they are by no means related.

The pseudobulds on these Dendrobium orchids are strong and rigid and carries up to six firm succulent leaves on the top of the bulb. The orchid flowers are borne right along the mature canes and does not really require any support like the nobile Dendrobium orchids. It is not uncommon to see a well established warmer-growing Dendrobium orchid that produces orchid flowers from the sides of the pseudobulbs as well as from its mature canes.

Since these Dendrobium orchids prefer hot, tropical conditions, it is important that you provide your cultivated orchid plant with the humidity that it would have experienced in its natural habitat. You also need to feed your Dendrobium orchid plants throughout the year so as to support the active growth and flowering of your orchids. It is best to feed them with high nitrogenous fertilizer during spring to aid the growth boost and then follow the feeding up with a general type of fertilizer during summer and a bloom booster in fall/autumn.

These Dendrobium orchids should be repotted just after the flowering period which can be throughout the year. The compost mixture that you use for potting your Dendrobium orchid should be free-draining so as to accommodate regular watering without the risk of over-watering which might result in rot. On the other hand, if you cultivate your orchids outside attached to a tree, rainfall will readily soak the orchid plants as well as drain through the medium on which the orchid plant is attached.

Light is yet again very important when cultivating Dendrobium orchids, even more so when you are cultivating your Dendrobium orchid in a green- or shade house. When repotting or potting your orchid plants be sure to make use of a very solid pot (It is recommended to make use of a clay pot because of its heavy base) as the Dendrobium orchid has a tendency to become top-heavy. In its favor, this warmer-growing Dendrobium orchid also lends itself to basket culture.

General tips when growing Dendrobium orchids

• When these plants are grown in the home, we recommend that they be placed outside in the fall to benefit from the cooler temperatures at night and brought inside just before the onset of freezing weather. They then need to be put into a relatively cool location (such as an unheated room or an enclosed porch) until buds start to form. These are especially true if you are cultivating the intermediate-growing Dendrobium orchids.
• Dendrobium orchids are one of the few types of orchids that will bloom from the old pseudobulbs/canes, and they also bloom from the new growth.
• The warmer-growing Dendrobium orchid species can bloom throughout the year and it is important that repotting for these orchids be done as soon as possible after the flowering period.