|Dendrobium Red Emperor 'Prince'|
Dendrobium nobile hybrids are seldom seen at retail outlets, unlike the ubiquitous Dendrobium phalaenopsis hybrids which you are probably familiar with. Dendrobium is a huge genus, widespread throughout Asia and diverse in morphology. Thus, there are many types (the group is divided into sections) of dendrobiums with different cultural requirements.
The Yamamoto Dendrobium website gives an illuminating description of the habitat: The nobile type Dendrobiums are native to SE Asia and grow on branches of tall trees (read: needs very bright light) in cool areas up to 3,000 ft. elevation where night temperatures may drop near freezing in winter (read: cold temps are required in winter for bud initiation). There are two seasons: rainy summer and a dry winter in which there is very little rain for four months.'
In a nutshell: warm moist slightly shaded summer followed by cool dry full sun winter. We grow our plants in a 50% shade humid greenhouse and move them to a cold greenhouse (53 to 55 º nights) from November to New Year's.
The folks at Yamamoto have produced some terrific pages with detailed cultural information. If you are buying Dendrobium nobiles at our Gently Used Plant Sale I would recommend that you keep them at 55º to 75º in order to maximize the longevity of the flowers.