Dendrobium primulinum, also known recently as Den. polyanthum
I have had this orchid plant for about five years and I have found it is among the easiest to grow among my Dendrobiums…..unfortunately easy to grow doesn't necessarily means it is also easy to bloom. Dendrobiums I have in my collection have grown well with what I consider standard care for members of the Dendrobium section according to culture, but getting these plants to bloom has been at times a source of frustration and disappointment.
I grow this species at the highest range limitations of temperature tolerance to produce buds…..giving them the right low temperatures at night on rest periods to reward me with good quality and quantity of flowers.
I give this full sun in the morning during the warmer months outdoors….in the colder months they come inside in the south facing bay window where they get more sun as autumn goes into winter, this is similar to what happens in their native habitat where they are exposed to brighter light conditions when the trees where they cling to lose their leaves.
This orchid plant gets watered every other day from May to November and then I hold watering and fertilizer for two or three weeks in mid-December….. I watch the canes and if they get too wrinkled I water the plant lightly.
I have three types of premulinum:
Dendrobium primulinum
On my older thread, the flowers have bluish petals and sepals and a white lip.
Another has all white lip with two yellow eyes and baby pink sepals and petals. (I have seen another member post this kind)
The third type are the flowers that you see on this thread that has so much yellow in the lip that it resembles a Dendrobium farmeri flower, the petals and sepals of this flower are light pink.
I have seen some plants that have been offered for sale on Ebay as primulinum alba, but the ones I have seen in person appear to be white versions similar to the species Dendrobium cretaceum.