Wednesday, February 2, 2011

Nobile Dendrobiums - The Section Eugenanthe.

Nobile dendrobiums are a section of attractive dendrobiums that share a name similar to the dendrobiums(Phalenopsis type) that we normally see but require totally different cultural conditions.  They are found in the Himalayas in the North East of India and also at higher elevations in the Western Ghats. Unlike the phalenopsis type dendrobiums that are evergreen and require even watering throughout the year, the members of this section require a cool winter rest so as to bloom in spring. To understand and grow these plants successfully, we need to understand the environment in which these plants grow. Making a little adaptation to mimic the climatic conditions in the North East should give good results.

The montane regions in India have a very distinct climate that is quite different from the plains of India. During the months of June to September and to a lesser extent in October and November, these areas are drenched by the South West monsoons keeping these plants constantly wet. Their roots are surrounded by mosses and ferns which also take the opportunity to grow given the increased humidity. Added to that, the lush vegetation above and the cloud cover decreases the amount of sunlight incident on the plant. It is during this phase that the plant grows. As the monsoons begin to withdraw and the intensity of the light increases, the plants which have by now completed their growth begin to shed their leaves; a protective mechanism to store water and prevent transpiration.  At the same time, the cold winds from the Himalayas set in and cool the plants to a considerable level. The plants go into hibernation and seem like dead twigs hanging from the branches of trees. During February and March when the climate is considerably warmer, they burst into blooms with beautiful flowers.



Coming to the culture of these plants, it is better to have them mounted pendulous as they are found in nature on a little slab of tree-fern or a small  6 x 3 inches teak panel about a centimeter thick with a little moss or coco husk tied around the roots to stabilize the plant. During the monsoons the plant will rapidly send off roots and attach itself to the media. Fertilizer can also be given to the plant during the monsoon period. Towards October, watering should be considerably reduced with just a little spraying in the morning to keep the canes from shriveling. Reduce fertilizer too during this period. A good indicator as to when to stop watering is yellowing of leaves. Once the leaves start dropping off, water must be reduced accordingly. As November and December approaches, watering should be done sparingly and fertilizer completely stopped. Light conditions should also be increased during this time. If this is done, you should expect blooms in January and February in the plains while it might take a little longer to bloom in colder places. If watering and fertilizer are not reduced, you will find your plant sending off plenty of baby plants on their canes and flowering will be markedly reduced.

                                                     Den. cucullatum

Another problem in the plains is the heat of the summer which these plants do not experience in their natural environment. So once the plants are done blooming it is necessary to protect them from heat until the monsoons begin. Some of the species that do well in the plains are Den. cucullatum, fimbriatum, pendulum, anosmum, macrostachyum, friedericksianum, parishii, bensoniae and signatum. Some others that will do well given a little colder climate and protection during the summer are heterocarpum, nobile, primulinum, aqueum, crepidatum, lituiflorum, ochreatum and chrysanthum.  Hybrids of species from the first group are becoming popular as they are more floriferous with longer lasting flowers and cope better with the heat.