Try the Hoya forum on this website:

http://www.gardenweb.com/


Wishy13764 wrote:

2 of my hoya's which bloomed for me a couple of times this summer, are
starting to shed some yellow leaves. I make sure not to overwater..once a
week should do it, and of course they are potbound, or they would refuse
to bloom. Most experts say not to fertilize Hoya's too much and I hardly
do that. What other reason could there be why some leaves are turning
yellow. ..lack of nitrogen?

--
The Hawke