Vivi's Orchid Corner

December 2001 - Volume 6, Issue 10

"Nobile-type Dendrobiums"

Dear Orchid Friends:

Dendrobium nobile species include nearly 80-100 named varieties and are native to Thailand, India and the new World Tropics and are popular throughout the world. Nobile-type dendrobiums are quite adaptable and grow both in low elevations to high mountain elevations, contributing to their popularity. While traveling in Brazil several years ago, I found the Dendrobium nobile were in bloom and were everywhere. These orchids are extremely popular in Brazil. These are hardy species - tolerating temperature extremes. Dendrobium nobile are widely grown in Hawaii and much of our supply comes from Hawaiian, Taiwan and Korean growers.

The genus dendrobium are generally classified into six basic groups based on similar growing habits, conditions, characteristics. Nobile-type dendrobiums are classified under Group I. These are deciduous orchids( they drop their leaves) and are called cane orchids. Dendrobium nobile do not lose their leaves until its second year. This group of dendrobiums like changes in temperatures at different seasons.

Group I dendrobiums contain species such as: Dendrobium chrysanthum, Dendrobium falconeri, Dendrobium fimbriatum. Nobile-type dendrobiums are upright species with thicker canes. Many dendrobium hybrids are offspring of Dendrobium nobile.

FLOWERS: Flowers are deliciously fragrant. Flowers are borne on short stems so flowers remain close to the main stalk. They do not have long inflorescences. A healthy plant will produce numerous flowers - a "bouquet" of brilliant flowers. Dendrobium nobile usually flower late fall through spring. Flowers are rounder with ruffles lips and usually have a maroon throat. Flower petals come in a variety of brilliant colors: pink, magenta, yellow, white. Blooms are long lasting.

TEMPERATURES: These orchids need a temperature variation to induce flowering. They like cool nights in Autumn and Winter (40-50 F). During their season of new growth, which is spring to summer, they thrive on warm temperatures and bright sunshine. Grow them with your cattleyas during these warmer months. During the winter, they require cool night temperatures with a fluctuation from day to night temperatures. Flowers will last longer if placed in cooler environments while in full bloom. The temperature change is essential for their flowering cycle.

LIGHT: Nobile-type orchids love sunlight and sunshine. These orchids tolerate full sun! Full sun promotes vigorous growth. Do give some shade and protection to your plants when flower buds begin to form and until end of their flowering to extend flower life. But sunshine is their energy source.

WATER: Nobile -type orchids require a drastic change in their watering schedule from summer to winter. They require periods of considerable water coupled with a period of dryness and nearly no water at all. This is called the COOL - DRY TREATMENT!

Water vigorously during active growth which is generally spring through summer. During spring months, increase your watering and in the hot summer months water very well. Fertilize heavily in summer months. In the fall, begin to cut back on your watering on a gradual basis. In South Florida, you may still require more water until November or December. When the night temperatures fall below 70 F, cut back on your watering even more. Continue to decrease your watering as night temperatures become lower. In the winter months, water just enough to keep the orchid from becoming dehydrated and shriveled. Reduce your fertilizing in the winter months also. Basically, forget about them.

The most difficult thing about Nobile-type orchids is to maintain the "Cool - Dry Treatment". Most of us over-water our orchids and it is difficult to change our habits. Try to refrain from over-nurturing these dendrobiums in the winter months. Barely water them! When the flower buds are well formed, begin to increase your watering. The "Cool - Dry Treatment" is essential so your orchid produces flowers. Do give them sunlight during the winter months.

Nobile - type dendrobiums can produce keikis, or small off-shoots. To prevent an over-abundance of keiki growth, give them high levels of light. If keikis occur near the pseudobulbs, remove them to promote the development of the main shoots. Keikis can be removed and potted to give you another plant!

Nobile-type dendrobiums may be a little more difficult to master because of our tendency to over-water and over-nurture and the necessity to maintain the "Cool - Dry Treatment". These orchids do extremely well outdoors and in South Florida they can be left outside nearly year round. Remember to give them plenty of full sun and water in the summer; sun and cool nights with little water in the winter. That’s the secret!

Vivi