Hoya Care Guide
over 500 accepted species within this genus, making Hoya a diverse group of plants. Native to several countries in Asia, as well as some species in Australia, this group of plants also goes by the name waxvine or waxflower due to their flowers appearing to be made from wax. Though there are hundreds of species of hoya, there are only a few sold as houseplants. These few have been bred to have fantastic diversity, sometimes making it hard to believe that they are the same species! The most common in cultivation are Hoya carnosa, Hoya pubicalyx, and Hoya kerrii. H. carnosa is the most common and possibly most varied, as both Krimson Queen and Hindu Rope are cultivars of this species. While each species has its own minute differences in care, overall the entire genus can thrive with the same care as a houseplant.
While they can occasionally tolerate lower light conditions, hoya thrive in bright, indirect light. Without proper lighting, these plants will not flower and will etiolate. Etiolation occurs when plants stretch and reach for the light. Etiolated plants are often described as leggy. The brighter the light, the more fragrant flowers and vibrant foliage to enjoy! Be sure not to put the plant in direct sunlight for more than a few hours a day, this can cause sunburn to occur on the leaves, which will remain for the life of the leaf. Keeping these plants in or near a bright window will be perfect. A grow light can supplement lower light areas, though be sure to keep the lights a sufficient distance from the leaves to prevent burns. The minimum distance from the leaves varies depending upon the brand and model of the lights; many will have the recommended distance listed on the packaging. If not, 15-24 inches above the highest point of the plant is a good rule to follow that will apply to most grow lights.
Hoya are very drought tolerant plants. It should not be watered until the soil in the pot is completely dry. The leaves of hoya are usually firm and rigid, though, when they need water, they become slightly pliable. When watering, do not give a small amount of water at a time. Overwatering is not the quantity of water, but the frequency. The proper way to water is to soak the substrate of the pot thoroughly, no matter if you are watering from the top or the bottom. From the top, this is best achieved by watering until excess drains from the holes in the bottom of the pot, then continuing to add water for a few more seconds to ensure every spot in the pot has been saturated. If watering from the bottom, be sure to add enough water to the tray you are soaking it in that will saturate the pot and allow the pot to sit in the water until the top of the soil appears damp, as well. At least within the top inch. Depending on the size of the pot, this could take minutes to hours. Allowing your plant to soak for an entire day will not be detrimental if the soil is allowed to properly dry between watering.
It is possible to have a hoya thrive in typical potting soil, though often times regular potting mix does not dry quickly or completely enough and can lead to root rot. It is best to have a chunky soil fortified with nutrients. The aroid soil I offer in my shop is perfect! Not only will this help to prevent over watering, it will give the roots a chance to breathe (Find it here! https://cedarbridgebotanicals.com/collections/frontpage/products/aroid-soil ). Well drained succulent soils also work well. Many times, hoya will be sold in a chunky soil mix. If this is the case, it is perfectly fine to leave the hoya in the nursery pot until it out grows it! If not, and the hoya is sold in something more closely resembling regular potting soil, you may want to consider replacing the soil with something faster draining.
Like many beginner friendly houseplants, hoya tend to be fairly disease resistant, but that doesn't mean disease immune. Here are a few common problems you may experience with your hoya.
This may be the most common problem associated with hoya. This is caused by water sitting on the roots for a prolonged amount of time, limiting the gas exchange that is able to be performed by the roots, suffocating them. Often, hoya will drop leaves as a symptom of root rot. If it is just one or two of the oldest leaves, this shouldn't cause alarm, as this is a natural process. Just like you can't keep every hair on your head, plants can't keep every leaf they make. However, if they drop several old leaves, new growth, or especially both, check the roots for rot. Dead roots will be thready in appearance. Healthy roots will be plump and firm. Adjusting your watering to ensure the soil is completely dry before watering again should solve this problem. If the plant does not recover within a few weeks, remove all of the unhealthy roots and repot in chunky, well draining soil.
Sooty mold is easy to treat, however it doesn't usually occur without the presence of a pest. Sooty mold commonly grows on honeydew, the sugary excrement secreted by many plant pests including aphids, scale, and mealybugs. Simply wipe the mold from the leaves and stems and treat with a mild fungicide spray. However, this will likely only be a temporary solution until the pests producing honeydew are treated.
Mealybugs are a white, sap-sucking insect that produces the honeydew mentioned above. They often hide on the underside of leaves and in tight crevices of new growth. They are easily treated with pesticides, an alcohol mixture, or beneficial insects. For more information on how to identify and treat mealybugs, check out the blog post titled Mealybugs and How to Deal with Them.
Aphids are another sap sucking insect that commonly afflict hoya plants. They are usually found on the stems near the new growth and also secrete the pesky honeydew. They can sometimes be blasted off of the plant with a strong jet of water, or treated with either a systemic pesticide or and insecticidal soap. Many beneficial insects prey on aphids! Ladybugs are the first to many of our minds, however, green lacewing larvae eat far more aphids than ladybugs! As an adult, green lacewings drink nectar and act as pollinators. For those reasons, I personally prefer to utilize green lacewings to help control any aphids that may arise on my plants.
Overall, hoya are a great beginner plant that love bright light and dry soils. If cared for properly, they will give you beautiful, fragrant blooms! They're a lovely beginner plant with the added bonus of being pet safe and relatively disease resistant!