Many Hoya's bloom in response to day length. H. carnosa is more prone to bloom spring/summer thru early fall, but will bloom during the winter if it's happy.
Hoya australis, magnifica, calycina are fall bloomers in response to shorter days. Some will bloom only during the summer when the days are really long. Some need cool tempertures to bloom, like H. globulosa. It grows wonderfully for me. But I just don't have the temperatures that it likes to bloom, so I just enjoy the foliage.
