Articles About Orchids
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Articles About Orchids
A NOBLE WINTER ORCHID
Dendrobium nobile   
   It is beginning to look like winter here in the Orchid Garden. All the leaves in their vivid fall colors have fallen to the ground forgotten for another year. Old man winter is blowing his frosty breath on the plants and trees sending them cold and shivering to their winter beds. Believe it or not, there are some orchids that love this winter weather and have evolved needing the cold to help them prepare to burst forth into full spring colors. If it gets near freezing and even sometimes an occasional light frost where you live, these orchids would love to call your garden home.

   This group of orchids belongs to the "noble" Dendrobium genus. Do not confuse these Dendrobiums with the warmer growing Dendrobium phalaenopsis types, that are found in many of the stores. The easiest way to tell them apart is the D. phalaenopsis types have long branching flowering inflorescence and the D. nobile types produce their flowers attached to the canes.
   Members of this "Dendrobium nobile" type orchids are grouped together based on their similar environmental requirements. Most of the species mentioned in this article are native to regions north of the Tropic of Cancer, these orchids can hardly be described as tropical.
   With the change of the day-length and cooler night temperatures of the coming winter, the nobile Dendrobiums and their hybrids begin to make their transition preparing for their winter nap. Their leaves turn yellow and fall off, not needing them for the next few months. By the time winter arrives they will be in a complete dormant condition.
   From November to February keep the plants dry. A light spraying is permissible if the canes are very shriveled but should not be necessary. Provide lots of light and good air circulation. By spring the plants will look very neglected with shriveled pseudobulbs and no leaves and if you did not know better you would think they were dead and ready for the trash heap.
   In February the signs of growth activity should be appearing. After the cold of winter, they prefer day temperatures of 13 oC to 29 oC and night temperatures around 10 oC. From March to the end for August the growing period begins and you will see new growth and leaves. New roots may not be seen until April when the flowering becomes established.
    If the nobiles did not receive sufficient cold during the winter they will produce keikis instead of flowers. If you provide them with their particular needs during the winter, they will produce fragrant flowers which emerge from the top of their canes all the way down to the roots. These orchids are very fragrant and will fill your garden with their seducing scent. Many of the hybrids of this type have been bred and trained so the “canes” are grown upright.
Dendrobium nobile
   The weight of the flowers often will bend the canes back to the normal pendulous shape.
   Thanks to the hybridizes they have been able to produced some selected clones of species and hybrids that have been hybridized for people who cannot cultivate the cold growing nobiles in their homes/greenhouses.
   In November I have beautiful flowers appearing on some of my nobiles. As the days shorten many of my nobiles will produce flowers in the fall without giving them the very cold temperatures. I keep my greenhouse in around 16 °c during the night and I do reduce the water during the winter. D. findleyanum ‘Sailor Boy’ blooms in November for me. This species grows in the mountains of Burma and Thailand.
   Dendrobium nobile is one of the relatively few orchid species, which is rich in alkaloids and is used in traditional Chinese medicine, in the "Chin Shih Hu" herbal tea cooked from its dried stems. The extract has tonic and antipyretic effects. This species contains over a dozen alkaloids and the first alkaloide from any orchid species (called nobiline), was isolated from D. nobile by Japanese scientists, in 1932.
   With this "first" D. nobile played an important role in orchid alkaloide research.
Some of the cool growing nobile types worth growing are D. wardianum, which is native to the mountains of Assam, Burma and Thailand.
Dendrobium nobile painting by Sue Abonyi
    D. falconeri is a close relative of this species; D. gratiosissimum, D. lituiflorum and D. transparens all feature very fragrant flowers. The general rule as you pick and choose your Dendrobium is the size of the “canes/stems.” The thinner the stems are the more difficult it is to provide the proper dry, cold rest period for them. Remember if you get it wrong they will not bloom for you.
  You should follow these basic rules when growing orchids that require a dry rest and cool period.
1: Cold and dry   November, December, January and February
2: Warm and dry    Slowly increase moisture and temperature March, April and May.
3: Warm and wet     June, July and August keep the plants warm and wet; do not allow them to dry out.
4: Cooler but still warm    Temperatures and moisture should decrease in September and October.
   If you follow these simply rules your “winter orchids” should bloom every year for you. The main thing in growing these types of orchids is the hardest. Forget them!
   Don’t pamper them and worry over them like an old mother chicken with her chicks. If you pick up the watering can or raise the thermostat just once can interrupt old mother nature's sleep and your orchids will not bloom. Be firm and you will be rewarded.