Native to Australia, Hoya australis grows naturally in rocky areas of its home continent and East Asia. It is considered an easy-to-grow Hoya variety. The blooms are known for their strong fragrance and attract butterflies when the plant is grown outdoors.
Hoya Australis Appearance
This hardy Hoya is a climbing vine and grows to 13 to 33 feet (4 to 10 m) long. The leaves are oval-shaped, shiny, and waxy in appearance. Leaves emerge red but turn green when mature. Depending on the subspecies, some leaves vary in size and can be fuzzy.
The star-shaped, white flowers grow in three-inch-wide clusters of 30 to 40 flowers. Each bloom features a red center and gives off a spicy-sweet scent some describe as a combination of chocolate and vanilla.
Hoya Australis Light Requirements
Place this Hoya plant in indirect light of a south-facing window for optimal growth. It will tolerate some direct morning sun, with the rupicola subspecies being the most sun tolerant. Overexposure to direct sunlight will cause leaves to scorch. Healthy leaves will range from dark green, with less sunlight, to yellowish green with more sun.
Do not place it in a dark area as blooming will be affected. It should be exposed to a minimum of six hours per day, more if grown in Northern climates with less sunlight. Use a full-spectrum LED light to supplement lighting if needed.
Watering and Soil
For the best Hoya australis care, grow this plant in well-draining soil. Let the top three inches of the plant’s soil dry before watering. Remove excess water from the drip tray to avoid root rot. The leaves store water, so watering every 10 days is recommended in spring and summer unless humidity levels are low. The plant requires less water when not in active growth.
Use a potting mix amended with perlite and orchid bark for faster drainage. Aim for a soil Ph level of 6.1 to 7.5 and use rainwater or filtered water if your area’s water is hard. Grow hanging plants in a basket to encourage air flow. Plastic pots trap moisture and may lead to overwatering or root rot.
Temperature and Humidity
Hoya australis prefers temperatures of 65 to 80 degrees Fahrenheit (18 to 26 Celsius). Do not keep them in temperatures below 45 degrees Fahrenheit (7 degrees Celsius) to avoid damage or dormancy.
Keep humidity levels between 40 to 60 percent. Higher humidity up to 80 percent is also acceptable. Increase humidity levels with either a humidifier or by placing the plant’s pot on top of a tray filled with gravel and water.
Pruning and Propagation
Prune dead leaves and vines for best Hoya australis care. Pruning of healthy vines is advised in spring once flowering is complete. Removing new growth may inhibit flowering as most blooming occurs here. Some varieties bloom on both new and old growth, so avoid over pruning.
Propagate this Hoya plant by cutting a stem with at least two nodes. Prepare a soil mixture of three parts perlite to one part peat in a small pot. Plant the cutting in the mix and cover the pot to maintain heat and humidity. Keep the pot at temperatures of 70 degrees Fahrenheit (21 degrees Celsius) or higher. Roots will grow within one month.
To propagate by seed, harvest a seed pod from an expired bloom and crack the pod open. Remove the seeds and immediately plant them in a small pot with the same perlite and peat moss mix described above.
Hoya Australis Pests and Disease
Mealybugs and whiteflies are the most common pests associated with Hoya australis. Mealybugs occur most often when temperatures and humidity is high. Pruning dead leaves will discourage infestation. Whiteflies release sticky honeydew that can discolor or kill the leaves of your Hoya plant. Use a horticultural oil, as directed, to cure infestations of either pest.
Root rot is common in all Hoya plants when overwatering occurs. Rid your Hoya of this disease by mixing one part 3 percent hydrogen peroxide with 2 parts water in a spritz bottle. Spray affected roots with the mixture, killing the bacteria causing the rot.
Hoya australis is one of the most popular varieties of Hoya plants readily available. It’s impressive vine length and fragrant blooms make it an excellent addition to any houseplant collection. These plants look beautiful and are efficient air purifiers for your home.
In a rush? Here are 10 Hoya varieties for beginners to discover:
Hoya Australis FAQ
Common subspecies include H. australis oramicola, H. australis rupicola, H. australis sana, H. australis sanae, H. australis tenuipes, and H. australis lisa.
With proper Hoya australis care, this is a rapid-growth variety with long vines.
No, Hoya plants are not considered toxic to pets or humans.
Use two bamboo hoops to act as a support for your Hoya plant. Choose a hoop length relative to the length of your plant’s longest vines. Insert both hoops into the plant’s pot in a crisscross pattern. Gently wrap long vines around the hoops and secure the vines with plant clips.
Ensure your Hoya plant is receiving at least six hours of indirect sunlight per day. No not grow it in a dark location and keep temperatures between 65 to 80 F and above 60 percent humidity. During the growing season, fertilize your plant with a suitable houseplant mixture every two to four weeks, as directed.