You usually see Hoya macgrillivrayi exhibit maroon coloured new growth but I would not be concerned with what you are seeing in your plant. Many other species have leaves that show the same colouration as your plant, Hoya subcalva comes to mind.

Mike

Karyn,
Just watch this plant closely and see if the variegation continues. If it does in the next two growth nodes, then perhaps you could cut this section off and root it.
You see some hoyas do this frequently. Hoya carnosa variegata, picta, rubra, krinkle-8 and compacta all have been derived from sporting as you are experiencing on your plant.
If your subcalva (BTW the name subcalva is incorrect, the true subcalva has never been collected ever to my knowledge) is showing signs of mutation, perhaps it is trying to make a new sport.

Can you explain to me what you mean by a true subcalva never having been collected? What makes one a 'true' subcalva, and the other 'false'?

The growth that Mike is referring to is new growth on subcalva as I know it. It grows in maroon colored, and as it grows larger, becomes all sorts of crazy colors, like pinks and oranges, with green around the edges and around the veins. Then as the leaf becomes fully grown, it settles into an allover green, like the rest of the plant. It happens quite often with my plant.

Thanks for the info. I was just concerned that this could be a virus. It's definitely pest free but that won't be for long. Once they go into the greenhouse for the winter they eventually get mealy bugs. I have brugs that send up variegated sports but it's always a new stem, not from growth on an existing stem. As long as it's nothing to be concerned about I'm happy. Now if it would just bloom I'd be thrilled.

If the true Hoya subcalva has not been collected I wonder what has been masquerading as Hoya subcalva all these years? I took a look in my Hoyas of North Eastern New Guinea but Hoya subcalva was not included.

Mike

Ted Green called so many hoyas so many wrong names. If you have followed his catalogs you will see the same image of a plant be called ten different things in ten years. He does not key out the species in any binomial fashion as most botanists do, instead he gets directly to the last page where it would say dichotomous venation and then he is set on calling the plant that name based on just one point of description. Chris Burton has had much of a controversial battle with names over her reign.
Hoya subcalva we have in circulation is closer to naumanii than it is to subcava. I will try to find the original description for this species and post it here. Subcalva has not been seen or collected to my knowledge. The grape scented hoya you have been growing as H subcalva has not been formally described or properly named yet.
It took decades for people to stop calling the black hoya as Hoya purpureo-fusca. Purpureo-fusca is a plamately veined species like a cinnamon leaf and has flowers that do resemble the pubicalyx red buttons in color, but is no way purpureo-fusca. I think we are all in agreement that the red buttons is nut purpureo-fusca. I hope we don;t have anyone listing this as such any more.

You occasionally still see the Hoya pupureo-fusca/pubicalyx mix up but not as often as in the past. I do see Hoya cinnamonifolia and Hoya cinnamonifolia var pupureo-fusca being used now and that makes more sense, well at least to me. lol

The flowers of the plant we have named as Hoya subcalva do closely resemble Hoya naumannii although naumannii's blooms are more slender in all parts. The plant we have as Hoya subcalva also has more narrow leaf bases vs naumannii. I would be interested in seeing the official description if you do have it available.

Mike