I received Hoya nervosa as an unrooted cutting from Ric Morier way back in 2015 when you could still buy cuttings for less than $15. I rooted it the traditional way in moist potting mix and began growing it inside of a tent in my basement. I had read online that this plant had taken someone five years to flower so I put off buying a cutting of it for a very long time as few people are in the market for a plant that could take so long to flower. Finally I just decided to pick up a cutting to round out an order and figured I could flower it much quicker than five years; that turned out to be wishful thinking!
My rooted cutting did well and was transplanted into larger pots several times over the years finally ending up in a 10 inch plastic pot. I used my regular chunky Hoya mix of 50% peat-based potting soil, 25% fine fir bark and 25% large perlite. I got really excited back in 2018 when I got a peduncle for the first time. I watched that thing like a hawk, but it never ever tried to bud up. I find these Hoyas that produce peduncles but never bud up, or attempt to flower among the most frustrating of all plants. After I had about five peduncles with no signs of budding up in a tent, I decided to put it outside for the summer for the first time in 2019. It was for naught, as I still got no buds. All I got for my trouble were a few sunburned leaves for my trouble.
Finally this year, the summer of 2021, I put the plant outside in my newest little greenhouse where it got very little sun. Midway though the season I literally could not believe my eyes when I spotted a peduncle that had started to bud up. I thought I was seeing things. Most of those first buds fell off for some reason, but the rest of the peduncles then all budded up at once and gave me a flowering bonanza. Usually flowers that look like the flowers on Hoya nervosa smell either highly sweet, or smell not at all. These flowers smelled exactly like freshly opened H. carnosa flowers; that is they have the fragrance of dark chocolate. I think that it fit this plant quite well!
Hoya nervosa is endemic to Vietnam and was first described in 1974. The name is in reference to the raised nerve like venation of the leaves. It makes a spectacular foliage plant even if you never get it to flower. If you really want to see the blooms be prepared to wait a very long time. I believe that only time can produce these flowers. Also, I don’t think that it can be flowered under lights, but needs a specific day length cycle, which is difficult to achieve artificially. It is a lovely plant that gets my highest recommendation!