Hoya darwinii was challenging to grow, let alone flower. It is definitely not a plant for the beginner, or for the windowsill. It seems to grow best in South Florida, the tropics and anywhere you can provide very high humidity. It is extremely susceptible to root rot and must be allowed to dry out thoroughly in a coarse mix such as one used to cultivate bonsai. I am unsure whether I will be able to get this one to live for me long term, but am fortunate that I had the opportunity to get to work with it for a time.