Hoya stenophylla was found on trees in the forest of the Torricelli Mountains of Northeastern New Guinea at about 800 meters of elevation. Hoya stenophylla was named as a species by Rudolf Schlechter. I have seen his name attached to a number of Hoya species so I did a little research on him and will share some of it here. Schlechter was born in 1872 in Berlin, Germany and was the 3rd of 6 children. He authored several works on orchids and proposed at least 1,000 species in Orichidaceae alone. He traveled the world extensively collecting plants and spent several years in what was then called German New Guinea. It was while living here in 1909 that he discovered H. stenophylla with the name meaning slender leaves. He died in 1925, leaving behind a vast herbarium, which sadly was destroyed in the bombing of Berlin in 1945.
This Hoya came to me in a trade made in September of 2021 when I traded a very talented grower and Instagram star from Phoenix a couple of H. thailandica plants for three plants of which Hoya stenophylla was one of them. It came as a rooted cutting growing in Pon, and I kept it this way for a couple of months, but it kept losing leaves, and I have a very difficult time to tell when to water this substrate. I eventually moved it over to tree fern where I barely watered it, and it seemed a little happier. I misted it every day and did not pay it a lot of attention. One day I noticed that one of its vines had twisted around a Hoya polystachya vine in my tent and was rapidly climbing to the top of the grow tent.
As I examined the slender little vine twirling around another Hoya vine, and climbing ever upward, I noticed something strange. One of the new leaves slowly pushing out seemed strange looking and the closer that I looked at it, I started to realize that it was a newly forming peduncle. I was ecstatic as I never really expected to flower this species as there were almost no photos of this plant online. I followed this peduncle with a magnifying glass for a couple of months as it tried to bud up. The earliest buds would blast but finally with very careful watering two buds held on and began to grow!
I was so very excited to come downstairs and examine these buds with a lighted magnifier every day. I think that most of the fun in growing these Hoyas is the anticipation brought on by bud development. This turned out to definitely be the case when the flowers finally opened on this plant. This is one of those Hoyas in which the flower only partially opens during the daylight hours; the corolla never fully extends even at night.
I believe that I may be the first person to flower Hoya stenophylla in the U.S. so I am going to lay out my exact conditions for those who want to try to duplicate the feat. Temperatures at night varied from a low of 59 degrees F to a high of 62 degrees F. The daytime temps varied from a low of 76 F to a high of 80 F. Humidity was always above 75%. The plant received 15 hours of indirect high output LED lighting. By indirect I mean that it did not hang directly under, but just off to the side of a light that was so powerful that it burned holes in the leaves of some of my other Hoyas such as H. icensis.
Hoya stenophylla is a very unusual, oddball Hoya that I feel privileged to have been lucky enough to flower. The plant is capable of blooming at a very young age and makes a very interesting specimen when just grown for the foliage. I don’t believe it will ever really be a mainstream houseplant as the conditions under which it grows are fairly exacting, bud for collectors who want to put in the effort, I can highly recommend the plant.