Wow, Alan, you sure have no need for "window treatments" in that room!
I've got 4 hoyas that seem to be doing pretty well, but like others I focus on enjoying their foliage. However, in the past year or so one of them has started blooming regularly (every month or two, and more blooms each time), and my little fishtail hoya is now budding out a couple of blooms for the second time.
I have a small H. lacunosa that's growing very slowly, but it looks pretty happy, so I'm reluctant to do anything much different with it. Superthrive can't hurt to try, though!
One thing I didn't know until Chantell told me a few years back... Hoyas will bloom repeatedly from the same little stub, so when the flower is fading, you can gently knock off the little blooms, but don't "pinch" off the cluster at its base!
