The plants and garden are at home in my province, and i can't just normally drop by every afternoon after office hours. It takes at least 4-5 hours to go home, so the most normal routine for me is going home every other week. However, just recently i made it a point, no matter how tired I am during the weekdays, to go home every weeked. And that is to keep track of my hoyas blooming for the first time. Seeing them change morphology from opening till a few days before they drop is also very interesting.
They normally open in the late afternoon, and starts emitting scents on the process. That is to attract insects for pollination, and the scent is even magnified at night luring the nocturnal insects like moths.
The flower buds take a longer time, from a few weeks to months from emergence to blooming. But even just the buds are consolation enough and very nice to photographs. This species is known to produce big almost round umbels, that really catch the fancy of both plain gardeners and addicts alike.
What about you, aren't you a hoya addict yet? I warned you! It is very contagious.