Hi Michele, my experience is when a leaf starts to get black spots and it cannot be rubbed off but is within the leaf it is a mold/fungus so I cut back on the watering and give it more air flow that usually takes care of it. The leaves affected do drop off eventually but taking them off stops any spread. Mold is a big issue for me since I live on an old riverbed, a block from a flowing river, and in the summer pull 5 gallons of water a day when it is humid from my basement and manage air flow. Is it possible to post a picture?
~ Mary

I believe I read online somewhere that black spots on hoya leaves could be a sign of too much sun. My carnosas have a few black spots on some of their leaves and I do remember some of the spots appearing after my hoyas were exposed to direct sun (by mistake). Is yours receiving any direct sun?

Planto

Both of you addressed the very reasons that I thought could be the problem. My Hoya is in direct sun (many leaves are yellow) so I thought that was the reason. My Hoya seems to love it where it is and that's why it is in the sun. It has shown so much growth and even has peduncles. I haven't been watering it too much. I do wait until the top two inches is dry before watering but have been thinking that mold could be another reason. I have added pictures of two separate leaves so you can have a better idea of what I'm seeing.

Thanks for your help so far!
Michelle

From what I can see it looks like black spot which is a fungus. I would check ehow there is an article about it and mixing natural fungicides such as vinegar and or soap. Using it out of the sun of course! I hope it gets better. ~ Mary