Hoya Myths Part 2 by Chris Burton

6. Hoya serpens is completely glabrous, i.e., lacking any hairs at all. That pure unadulterated crap! Hoya serpens is a small creeper with leaves about the size as the old US half-penny (now found on in coin collections). That is somewhat smaller than a US dime (10 cents) . Hoya serpens IS VERY DEFINITELY HAIRY. If yours isn't you DON'T have Hoya serpens. The best picture of it I have ever seen is on my page, The Hoya page. To see it, go to: http://www.succulent-plant.com/hoya.html Proof of this can be found in Sir J. D. Hooker's "Flora of British India, vol. 4, page 55, published in 1883. The author said of the leaves "papillose on both surfaces." Some clones have more hairs than others but all have some.

7. Hoya Myth #7 says that if a plant has milky white sap that it is a Hoya. Hogwash! Euphorbias have milky white sap. All of the Dischidias I've grown have milky white sap (don't know if all do or not). All of the Asclepias I've grown have milky white sap except for Asclepias tuberosa, which has clear to pale amber sap.

8. Hoya Myth #8 says that all Hoyas have milky white sap. Hogwash to that too. Hoya carnosa doesn't. It's sap is clear to pale amber in colour, as it that of Hoya pubicalyx. I've a yet to be identified species from China that has pale yellow flowers which has clear to pale yellow sap. There is a species from Vanuatu that Ted Green has recently said (wrongly in my opinion) is Hoya samoensis which he says has clear sap. He has since I've known him changed the label on this particular hoya four times so each of you may have it with a different label. He is partially correct about the sap. My observation while growing it for more than 25 years was that sometimes I'd take a cutting and the sap would be clear and another time it was white. Most hoya sap is rather thick and congeals rather quickly. The white sap on this one looks more like milk that has been diluted with water and when it dries it is rather powdery, unlike Hoya imperialis sap which is really gooey and congeals almost immediately into a rather hard white bead.

9. This myth says that hoyas do not absorb nutrients through their aerial roots. It also says that the aerial roots are there only for the purpose of climbing. That just isn't true. While it is true that hoyas do attach themselves by their aerial roots to rough surfaces and stick there, they don't need those roots to climb. They climb by twining. The rootlets, when they attach to something, provide stability but they also are used to absorb nutrients. I ran an experiment once using a big pot of the hairy leafed Hoya kerrii as the Guinea Pig. It isn't one I'm particularly fond of and I had another one at the time so I didn't really care if I lost it. I put the basket outside in a tree branch and left it all summer. I had just moved and didn't have the greenhouse built yet. All but a few of my hoyas had gone to the Atlanta Botanical Garden with a promise of cuttings from them when my greenhouse was ready. Well I didn't water that "Hairy Kerrie" (My pet name for that ugly thing) and we had a drought that year so it got little water all summer. By fall my greenhouse was done but I didn't think it a good time to start filling it with new cuttings so all that I put into it was that one lonely olf "Harry Kerrie" ---- I had strung up 12 ft. long chains every two feet across the entire 38 ft. length of my green house and on the benches had numerous pots of lava rock with tree fern poles planted in them. I was preparing for planting come spring. I didn't even bother to heat it. I hung the plant on a length of chain next to the SE wall and left it -- no food, no water, no heat, no nothing! It had a long stretch of wooden beams it could have attached it aerial roots to but never even attempted to do so. It didn't die either. It kept growing longer and longer and its aerial roots kept growing longer and longer. If it was receiving nutrients through those aerial roots, how did it survive a year without being watered? When I finally had everything in the greenhouse ready and I started planting, a year had passed since that plant had been watered. I finally took pity and watered the sorry looking thing. It was literally covered with red spider mites and had bled tiny drops of sap over most of it. I spray it good and after a couple of days sprayed it with Cygon. It took a couple of months but ended up becoming a right handsome plant. The only way it could have survived was from the nutrients in the air which were absorbed through those aerial roots. It certainly never used them for climbing. All five of the various Hoya kerrii forms, all known Hoya diversifolia and melifluas put out aerial rootlets in far greater abundance than other species. I have found those roots very colourful and as attractive as the flowers. They usually grow straight down and often to lengths of a foot or more, usually white to pale green in colour and almost always having red tips, at least all I've seen do. Colour may be dependent on light levels. I don't know.

10. Myth #10 says that "Hoyas are alkaline loving plants." There is much evidence that hoya's prefer acid to alkali. A very large percentage of hoyas are known to live in a symbiotic relationship with ants. They give hoyas shelter and pay the rent by nourishing the hoyas' roots with their own wastes. Ant waste is very high in formic acid. That says to me that an acid diet must be the preferred one.

11. Myth #11 says that "Hoyas are alkaline loving plants because the soil at the equator where they are native is limestone." That simply isn't true. In a rebuttal to all of these four myths (which my e-mail critic obviously didn't see) David Liddle who lives and has traveled extensively collecting hoyas wrote that in tropical Australia and in New Guinea the soil was based primarily on granite and basalt but with sandstone being most prominent in the desert areas of the Northwest. An HSI member who said he was a geologist by profession once wrote and corrected my and others' impression that granite might be alkaline. He said it most definite is not. A couple of trips to the library to read Encyclopedia Britannica convinced me that the areas surrounding the equator had soils just about as varied as any other parts of the globe.