by Mary Jane Parker, Master Gardener
I have a huge Hoya (Hoya carnosa) plant in my office. Also known as the wax plant or porcelain plant they are an incredibly long lived plant because the one I have has been with me for close to 30 years and it was supposedly at least 30 years old at that time. My hoya is probably the most common variety in cultivation – Hoya carnosa, native to tropical countries such as India, Japan, and Taiwan, but there are between 200 and 300 species in this family Apocynaceae (subfamily Asclepiadoideae) worldwide.
Hoyas are vines that climb by twining around structures, supports or trees outside in their native countries through the use of adventitious roots. They have simple leaves, arranged in an opposite pattern and mine has shiny leaves flecked with tiny silvery spots.
Hoyas require bright light to flower. My hoya flowers in spring and early summer and when it does flower, the scent is awesome and capable of perfuming a whole room. The flowers are star shaped, very light pink and produce abundant sticky nectar which can be a mess. Flowers are formed on spurs which get longer every year. Some of the spurs on my hoya has are at least 2 inches long.
Hoya carnosa has exhibited something called Crassulacean Acid Metabolism (CAM). As I understand it, CAM is the function that allows plants to store water for periods of time to use when there is none or very little for their basic functions. Like cacti in the desert – cool stuff!
Besides being an attractive houseplant, some Polynesian cultures use hoyas medicinally. Recent studies at the University of Georgia have also shown that Hoya carnosa is a good buffer against indoor pollutants. Another reason to love this plant!
Some links for more information about this very interesting plant