Hoya is not happy
New to Garden Web. I really need some help.
I don't know what kind of hoya I have, but it is not a happy camper. The leaves are oval-elongated and when healthy and happy, is a dark emerald green with blotchy silver-white spots on it. I took this hoya as a cutting from a friend's plant which bloomed profusely. This was 22 years ago - mine has never bloomed.
For the past couple years, my hoya is most unhappy - the leaves are pale, almost lime green, with dark green edge and veining, and it has lost most of its spots. It's not dropping leaves, however, quite the opposite - it's very actively growing more. I water my hoya carefully - only when the top couple inches of soil are dry. In the winter, water maybe once every 4 to 6 weeks. It is placed in our large East bay window where it gets about 3 hours of morning sun.
I was fertilizing with weak 20-20-20 hoping that would help, but if anything it started looking worse, so I quit that. Then, I thought maybe it was a buildup of minerals/salts in the soil, so last summer I dumped it out and replaced with entirely fresh sterile soil mixed with sand and added a good 2 inches of stones at the bottom of the pot and punched extra holes for drainage. I noticed there was only a small root system, which surprised me since there are about 15 branches each about a meter long and masses of leaves. I thought for sure it would be shocked with this treatment, but it just promptly shot out more stems and grew more leaves....which turned pale anemic green after a few months again. :( It's currently very actively growing in Dec/Jan!
No bugs on the plant. Just this morning, put it in the shower to wash the dust off (this is quite a project because it is rather big), but beforehand checked closely and no spider mites or scale or any flying/crawling critters anywhere.
What is making my hoya look so anemic and why won't it flower? (I don't know how to post pictures, sorry).
Your help is greatly appreciated.