Hoya sulawesiana is named after the island of Sulawesi where it is endemic. It is only known from South Sulawesi in Towuti and West Sulawesi in Mamuju. It is only found in lowland areas growing mostly epiphytically on small tree trunks about 15 feet up. It is usually growing in 50-70% sunshine with the leaves receiving the most light turning reddish/purple in color. The plant first made its appearance in social media posts by enthusiastic, Indonesian, Hoya collectors in 2018. It was noticed by plant scientists who then obtained samples; it was published as a new species June 17, 2019.
I received two samples of Hoya sulawesiana during the height of the pandemic in the summer of 2023. I have to say that this plant has not been the easiest for me to grow, and I have struggled mightily with it needing to restart it a number of times. This Hoya is an exceptionally slow growing plant in my experience, and if I had to guess why I have had so much difficulty with it, I would guess it is because I’ve watered it too much. Having hard waxy leaves, and in nature growing primarily epiphytically, it would require very little water. I finally, after two years, grew a decent looking specimen using mostly coconut husk chips as a substrate, and watering much less. This is a plant that can easily go two weeks without water.
Finally 2 1/2 years after obtaining it for the first time, I found a developing peduncle, which grew to over a foot long. It finally budded up, and I bloomed it from start to finish in a little under 3 years. It could have been done much sooner if I had gotten off to a better start with it.
According to the publication paper by S. Rahayu and M. Rodda, Hoya sulawesiana is most closely related to Hoya isabechanae. They are also both in the Acanthostemma section of Hoya and are both endemic to Sulawesi Island. There are however many differences with the biggest being the leaves of the two species.
Hoya sulawesiana is a plant that I have had my struggles with, but it is definitely worth picking up and trying it out for yourself. The leaves are amazing, and it makes a very worthwhile specimen given enough time. The flowers are beautiful, fuzzy and probably the largest in the Acanthstemma Section. For those reasons alone, it is worth searching out!