I have had many ups and downs with Hoya curtisii over the four years that I have had the plant.  First I had to learn how to grow it, which seemed to take at least three years.  Every time it would start to grow well, I would do something wrong, and all the new growing tips would dry up.  It does not like to have wet feet for very long, or it will immediately show its displeasure.  It needs relatively high humidity and to dry out between watering, followed by a good soak.

Early this spring I spent twenty minutes sitting down and thoroughly examining the plant looking for peduncles.  Let me tell you; they are difficult to find!  They are very small and camouflaged within the foliage.  After resorting to a magnifying glass, I found what looked like small peduncles with many annular rings where apparently it had aborted buds many times before.  In this photo you will see the rings that I am talking about:

Hoya curtisii Showing Small Buds and Rings on Peduncle.