Dendrobium thyrsiflorum is in Section Densiflora. Members of this Section have rectangular pseudobulbs, often atop thin cylindrical lower parts. They have a few leaves from near the apex of the pseudobulb. They flower in long pendant inflorescences from near the tops of pseudobulbs; this type of inflorescence is called a thyrse. Many have fragrant flowers, but flowers are not long-lived.
This Section comes from regions of Southeast Asia with a monsoonal climate. They tend to grow on deciduous trees. They have very wet and shady summers, then much brighter winters when the tree's leaves fall. Winters are much drier but there will be some dew. Depending on elevation some need a substantial cooling in winter, and other species don't. Note that the temperature information on IOSPE for these species refers to winter temperatures; all the species have warm to hot, wet summers. This plant is supposed to be a cool grower but it did fine through the summer in my very warm sunroom. It spent the winter outdoors with cool nights.
My plant came bare-root from Ecuagenera in January 2021. Kim (Fairorchids) bought similar plants at the same time, and wrote about them here.
Den. thyrsiflorum has a very wide natural range. It is from higher elevations so it takes very cool winter temperatures. I potted my plant into S/H in a 1-quart / liter plastic food container. and kept it outside on my sunny patio through the remainder of the 2021 winter. I would have brought it into the house had frost threatened but that didn't happen.
In the summer I moved it in my humid sunroom. It grew well but rats ate off all the new growths it has made since it arrived. This flowering is on a growth it already had.
When temperatures cooled down in Fall 2021 I moved it outside to a spot on my patio where it gets a considerable amount of winter sun. I did bring it in for a few days when frost threatened in December.
Unfortunately it's been open for a few days and I've detected no fragrance.
Edit: I just noticed Ecuagenera is having a sale May 4-8.
Dendrobium thyrsiflorum
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