It’s no wonder that Hoya callistophylla has made such a splash in the houseplant pool: the thick, light green leaves of this vining plant are contrasted by a deep, emerald green vein pattern unique to each leaf.
Top that combo with clusters of tiny white and pink flowers, and you’ve got yourself a winning combo for an easy-to-grow, beautiful vining houseplant that grows well in hanging baskets and on moss poles.
There’s no better way to experience a hoya plant than with the striking callistophylla, especially if you’re relatively new to the hoya family. These plants can grow to have incredibly long vines that stretch from one side of a room to the other.
History & Culture of Hoya Callistophylla
Often referred to as the “wax plant”, this hoya is a native of Southeast Asia, the Philippines, and Australia, though it’s thought to have first originated in Malaysia. It has hundreds of close relatives, ranging from the typical carnosa to more elaborate hoyas like compacta.
Hoya callistophylla is a slow-growing tropical vine that trails and curls around other plants in its natural habitat. Like other epiphytic plants, it can root in the cracks and crevices of tree bark where organic matter, such as leaf matter, has begun to degrade.
This hoya gets most of its moisture from the incredibly humid air and falling rain. It can also sap nutrients from its host plant, or gather them from decaying mosses and other matter that collects on the tree’s bark.
Hoyas became much more popular with the advent of social media and plant websites. Once plant collectors caught wind of a gorgeous, waxy vine laden with delicate little aromatic flowers, hoyas blew up in the houseplant industry.
Like most other plants that grow in tropical rainforests, Hoya callistophylla prefers light that closely resembles that of the sparse, yet bright rays that break through the upper canopy levels in the rainforest.
Despite the fact that most of us don’t have a living tropical rainforest in our houses (though we can always dream), the same levels of light can be reproduced in a household environment. Aim for bright, indirect sunlight, away from window sills where direct rays can burn those beautiful waxy leaves.
Instead, try to place your callistophylla adjacent to a window with Southern or Eastern exposure; this way, they still have access to bright light, but it’s diffused in such a way that helps minimize sun damage.
Hoyas like long hours of light, so try to choose a window that gets at least eight hours of light per day. If you place your hoya too near a bright window, it’ll let you know; you might notice browning leaf tips and spots beneath the waxy coating of its leaves.
Hoyas in general don’t like to be waterlogged, and Hoya callistophylla is no different. It is imperative not to let any water sit in the pot your hoya is in, which will inevitably lead to root rot and even death of your hoya.
Depending on the soil it’s planted in, the time of year, and the humidity in your house, watering schedules will look different for everyone. Instead of relying on a fixed schedule, try using a moisture meter or checking your hoya every day to see if it needs to be watered.
The growing medium should be dry in at least the top two inches before watering again, and any excess water should be allowed to drain away from the bottom of the pot freely. If you can, try to use distilled or at least filtered water, which are both similar to what’s available in the rainforest.
If your Hoya callistophylla is allowed to become too dry, its leaves may wilt and any flowers may fall from the vine. If this happens, soak the pot in a bowl of lukewarm water for ten minutes, then remove the pot and drain the water off. This should help reset the moisture situation in the pot.
Soil & Potting
Surprisingly, Hoya callistophylla doesn’t love to be potted in your standard, everyday potting mix. Hoyas need plenty of aeration from their growing medium, but at the same time, the growing medium should have at least some moisture retention capabilities.
That’s why it’s best to use a mixture of orchid bark, perlite, and either sphagnum moss or a coarse coco coir. The perlite helps to improve airflow amongst the larger chunks of medium, while the bark and coco coir or sphagnum moss help retain the right amount of moisture.
It’s always fun to pot your plants in decorative pots, but hear us out: you can plant your hoya in an orchid pot or pot with lots of drainage, then place that pot into your decorative option. There will still be airflow, and your hoya pot will look great at the same time.
Avoid using very porous pots like terracotta, which can wick the moisture out of your hoya’s growing medium faster than the plant can absorb it. Terracotta is great for plants that don’t need moisture, but it can quickly kill a vining epiphytic plant like Hoya callistophylla.
With plants that live the aerial way, humidity is key. Hoya callistophylla is one such plant that needs lots of humidity in order to grow properly. Without it, you might have a rather stunted, weak plant that doesn’t put on much new growth. Hoyas generally prefer between 40 and 70 percent humidity in their environments.
Now, there are a few ways to make sure your hoya has all the humidity it needs. If you have the patience and the memory to mist your hoya every day, this is a great option; you can mist the length of the vines and the undersides of the leaves daily to provide plenty of moisture.
The next option is to use a humidifier, which helps to maintain a consistent supply a humidity very similar to that of the plant’s natural habitat. All you have to do is remember to run at least one cycle each day within a close proximity to your hoya, and you’re set!
If mist just isn’t going to happen in your space, you can also try the tray method. Fill a shallow tray with pebbles and water, then place your hoya plant on top of the tray. As the water evaporates off the pebbles’ surface, a humidity bubble is created around your plant.
The types of fertilizer you give your hoya will change depending on the seasons. For dormant seasons, or when the plant is not in bloom or budding, use a nitrogen-rich fertilizer with a ratio of about 2:1:1 to support lush foliage and new growth.
However, when your hoya is budding or in bloom, switch to a fertilizer with a higher phosphorus content, such as a 1:2:1 or any similar ratio fertilizer. Always dilute fertilizers before applying, since hoyas can be sensitive to stronger formulas.
Be sure to fertilize at least once per month during the dormant season, and every two weeks when the plant is in full bloom. Once the last bloom falls away, you can dial back fertilizing to once per month again.
It’s good practice to flush out any fertilizer that builds up in the growing medium about once every six months. To do this, simply allow running water to flow through the pot for about five minutes, then allow the medium to dry halfway before watering again.
Repotting your hoya is just as easy as repotting any other plant in your indoor collection. First, choose a pot that’s about two sizes larger than the one your callistophylla is currently in. This sizing up helps allow for new root growth, but maintains the right amount of growing medium.
To repot, simply remove your hoya from its container, gently shake out loose growing medium, and fill the new pot about a third of the way full with the new medium. Arrange your plant so that the bottom leaves will sit jsut above the soil level.
Fill in the remaining space around the roots until the plant is stabilized, then water in the new medium, allowing all of the excess water to drain out. Keep an eye on watering for the next couple of weeks while the new medium builds up a moisture supply.
Be sure not to use a pot that has no drainage holes. Without proper drainage, your hoya will develop root rot, a fungal infection, and possibly even a root gnat infestation. Once you get the hang of watering the new medium, it’s all general care from there!