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
UK Royal Horticultural Society – Information on Hoyas
How to Grow and Flower Indestructible Hoyas
The Peterborough & Area Master Gardeners 
I am so thrilled to see this post Mary Jane.I am a member too who about a year ago was trying to find a member who knew about the Hoya flower,but was not getting much help then. What I have seen today is so exciting. Would you ever consider sharing a slip ? Respectfully yours
Joanne Artymko
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I was given this plant several years ago, and it always did really well, though it never flowered. But as of late, it started shedding leaves and I don’t know why it’s doing that. Unfortunately, I can’t see how to post the photo to show you.
I know it’s indestructible, but I’m still very concerned about this. Can you help. Someone suggested it has to do with watering, but is it too much or too little?
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In response to Dana’s question of fallen Hoya leaves: stop watering your Hoya since this plant doesn’t require much water in the Summer when it is actively growing, and certainly doesn’t need much, if any, water in the Winter. I have had a Hoya for 20 years and find that it thrives on neglect. Try not watering it any more this Winter and you may find that your Hoya will start to bloom. If your Hoya blooms, then start watering it with a little water once a week. Good luck!
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I moved from BC and brought my Hoya with me. But since then it has been slowly dying. Does anyone know what I can buy a Hoya? Or slips to start one?
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