Hoyas come in a wide range of varieties and are commonly referred to as the wax plant due to the waxy look of the flowers and leaves. The leaves are fleshy, much like a succulent, but it is a woody-stemmed vine that produces star- to rosette-shaped flowers.The flowers are white or pink with a reddish center and as they produce a spur is grown from the floret. These spurs increase in length with each cycle, looking much like the plant is trying to root. The plant can be grown in areas like Florida but are more preferred for indoors and are small (3- to 4-inch pots) or hanging displays.
Hoyas, or porcelain vines, come from Japan, China, Indo-China, Australia and some from the Pacific Islands. The plant does best in full sun in a small pot. Many growers believe they have to be root bound to do well, but consistent biannual re-potting in a coarse potting mix yields flowers.
Growing a Hoya should start with a good node cutting. Ideally the cutting should produce a shoot within three to four weeks of planting. Cuttings should be placed so the node is near the surface of the soil and the roots will run down from the node. It can take many months before the cutting is sufficiently rooted to place it in a larger pot. The cutting should be in bright light and high humidity, or misted frequently. The propagation takes a good deal of patience and diligence.
Hoyas are in the Asclepias family or common milkweed. They all produce a milky sap laden with latex and are considered toxic. This does not necessarily mean they are poisonous; however, the effects vary with the species and size of the animal that ingests the leaves. The University of Washington's "Poisonous Plants Booklet" lists Hoya as nontoxic, but since there are many varieties and many different reactions to plant compounds, it would be best to keep them out of the reach of pets and children. Additionally, anyone with an allergy to latex should avoid handling the plant if it is damaged.
There is a wild growing milkweed called poison milkweed or Asclepias subverticillata which has been shown to contain high levels of toxic compounds. It grows wild in Santa Fe and other areas and it is most dangerous to grazing animals. The levels of latex in the plant are the culprit and can present physical signs in persons that do not wash their hands after handling or ingesting it. This plant is classified with a low to moderate toxicity.
Preventions and Solution
Although the houseplant Asclepias has very low toxicity and should not prove poisonous, the worried owner can take precautions. Keep the plant in a hanging basket high enough that children and pets can't chew on the leaves. When making cuttings or removing damaged vines, wear gloves to avoid contact with the sap. Also, do not rub your eyes or any other exposed skin until you have washed your hands thoroughly.