Whether you’re brand new to gardening or a seasoned professional, the Hoya Australis will make a beautiful addition to your collection of houseplants. Hoyas make up a wide range of subspecies (often abbreviated as ssp.), and the Australis is among the most popular.
This green grower is often called the Wax Plant or Waxvine because of its waxy leaves, though Hoya Australis‘ flowers are just as distinctive. It’s great for all skill levels because of its general hardiness and environmental adaptability. The following sections will provide an in-depth look into the world of growing the Hoya Australis. For your convenience, reference the bulleted information for quick tips and tricks.
Hoya Australis Flowers
The Australis is becoming increasingly popular among the Hoya cultivars because of its flower’s fragrance and beauty. The plant’s blooming portion has been called the Wax Flower or Porcelain flower because of its waxy, sculpted appearance and texture. The flowers start growing in the cooler, late winter months and bloom fully through the summer, attracting butterflies in their natural habitat.
With a sweet-smelling aroma, the Hoya Australis‘ white flowers have a bit of red at each petal base, usually growing up to 3 inches in total diameter. The flower base consists of “spurs” and “peduncles,” where the flower heads emerge each year. Please don’t cut them off, or you won’t get any new flowers!
How Do You Care for a Hoya Australis?
As you may have guessed from the name, the Hoya Australis is a native plant to Australia and the greater Oceanic region. With its succulent-like leaves, Hoya Australis is well suited for northern Australia’s arid climate while also thriving in the South Pacific Islands’ wetter conditions. For your convenience, we’ve created a bulleted list of care tips and extra tricks to get the most out of your Hoya houseplant.
- Scientific/Common Name: Hoya Australis – Waxvine, Waxflower
- Genus: Hoya
- Scientific Family: Apocynaceae
- Origin: Australia, Indonesia, South Pacific Islands
- Distinguishing Features: Waxy, green succulent-like leaves and similarly waxy, white and red petals
- Home Placement: Away from hot or cold windows, ideally West, East, or North-facing
- Growth Speed: Fast-growing, climbing vine
- Mature Height: 3 to 30 feet, depending on growing conditions/support
- Light Requirements: Bright, indirect, filtered sunlight
- Watering Requirements: Water infrequently, only when soil is dry. Mist regularly to simulate humidity.
- Soil Requirements: Well-draining, well-aerated mixture of organic materials.
- Fertilizer: A ratio of 2:1:2 or 3:1:2 (Nitrogen to Phosphorus to Potassium) is sufficient. When flowering, switch to a higher Phosphorus number to encourage blooming.
- Temperature: 65º to 75ºF (18º – 24ºC) – Avoid temperature extremes
- Humidity: Greater than 60% is ideal but can survive in typical home environments
- Flowering: Sweet-Smelling Fragrance, White Petals with Red Spots, blooms in bunches after Spring, Waxy texture about 3 inches in diameter
- Pruning: Prune to control the shape and growth pattern. Remove dead leaves and flowers as necessary. Watch out for sticky sap when pruning.
- Propagation: Propagate in the Spring. Cut a healthy stem (about 5 inches long) with at least two leaves—pot in a well-draining, well-aerated mixture like the original plant.
- Repotting: Only repot if roots are visible above the soil. Hoya Australis does not take well to root disturbance. Only repot if necessary, likely after 2 or 3 years.
- Diseases & Pests: Root Rot, Mold (from excess sap), Aphids, Mealybugs
- Toxicity: Technically non-toxic, child and pet friendly. However, the sap and leaves can cause mild illness.
Hoya Australis Soil & Potting Requirements
Hoya Australis likes a potting mix rich in organic materials like perlite and compost. Most Hoyas are “epiphytic,” meaning they naturally grow on other plants, though not in a parasitic way. Organic components in the soil you choose will help mimic the living hosts on which the Hoya Australis lives. Make sure to use a well-aerated mix with good drainage to avoid suffocation and waterlogging. Something too dense, like garden soil, will choke out the roots and retain too much water.
Similar to the potting mix, the pot you choose also needs to have sufficient drainage. Make sure the pot has drainage holes, and consider lining the bottom with stones for added drainage and aeration. Clay or terracotta pots are best because of their porousness, and they will firmly contain the Hoya Australis‘ robust root system.
Fertilizer is not necessary for the Hoya Australis, but if you want to boost your houseplant‘s growth, anything with a ratio of 2:1:2 or 3:1:2 (Nitrogen to Phosphorus to Potassium) is sufficient. When flowering, switch to a higher Phosphorus number to encourage blooming. Since Hoyas are succulent-like, succulent food will also work well. Hoya Australis shares enough qualities with Orchids (flowering and epiphytic) that many gardeners use Orchid fertilizers on this species of Hoya.
Sunlight Requirements for Hoya Australis
Though the growing season is primarily in the spring, Hoya Australis will survive all year long because of its sunlight adaptability. While it could not live in a cold-weather environment outdoors, most homes are not nearly cold enough to stifle Hoyas‘ growth. As long as it is kept away from temperature extremes, like a particularly hot or cold window, Hoya Australis can do well in any home. However, west, east, and north-facing windows are ideal. This climbing vine will quickly grow to a standard two or three feet with the right lighting conditions. If a suitable support system is in place, Hoya Australis can grow over thirty feet tall!
Do Hoya Plants Like Direct Sunlight?
Do Hoyas like the sun or the shade? Well, the Hoya Australis does not do well in direct sunlight. The sun’s radiant heat can scorch the leaves and flowers while also drying out the soil too quickly. However, don’t mistake Hoyas for low-light houseplants–– they need plenty of bright, indirect light. It can survive in low-light conditions but will never reach its full potential. Place your potted plant a few feet away from a sunny window or on the other side of sheer curtains for filtered sunlight. If you notice browning leaves, dropping petals, or a need for watering more than twice a week, your Hoya Australis is likely receiving too much direct, unfiltered light.
Watering & Humidity
Since Hoya Australis shares many qualities with succulents, they retain water well and are resistant to drought. They don’t like soggy roots or heavy soil, similar to other epiphytes like bromeliads and orchids. Utilize a pot with drainage holes, a potting mix with good aeration, and avoid overwatering. If you notice a need for watering more than twice a week, your Hoya Australis is likely receiving too much direct light and heat. Pull the plant away from the sun to reduce its watering frequency. Hoya Australis needs watering once a week during summer but can tolerate once every two or three weeks in the winter.
Do Hoyas Like to be Misted?
To avoid overwatering, misting can be a helpful alternative for moistening the Hoya Australis. A full-on watering may be unnecessary, whereas misting the plant can provide enough water to satisfy its thirst. Water infrequently, only when the soil is dry. But mist regularly to simulate humidity. A spray bottle or humidifier will also mimic the humid conditions Hoyas love. Humidity higher than 60% is ideal, but the Australis can survive (and thrive!) in typical home environments. It also does well in average household temperatures of 65º to 75ºF (18º – 24ºC). However, avoid temperature extremes, whether too hot or too cold.
Pruning & Propagating Hoya
If the Hoya Australis is growing beyond your control or preference, prune it for visual and spatial maintenance. Pruning helps revitalize your plant’s life and stimulate growth if it has had some recent struggles. Use a knife or a pair of very sharp kitchen shears to remove any dead or unwanted leaves, but let as many green leaves remain as possible. Hoya Australis can reach heights greater than thirty feet in ideal growing conditions, so pruning will keep it more manageable for your living space. Watch out for the sticky sap that will leak out of any cuts. If you want to prune the flowers, remember that the base consists of the “spur” and the “peduncle.” These are where the flower heads emerge from each year, so don’t cut them off, or you won’t get any new flowers!
Propagation is a simple extension of the pruning process to create more Hoya Australis plants. These can fill up the rest of your home, or you can give them away as gifts! Propagation is best done in the spring when the plant is growing most rapidly. Cut off a healthy stem (about five inches long) with at least two leaves; otherwise, it is unlikely to regrow. Use a knife or a pair of very sharp kitchen shears and watch out for the sticky sap that will leak out of any cuts. Don’t remove more than a third of the plant at a time, or you’ll risk killing it. Plant the fresh cutting in a well-draining, well-aerated mixture like the original plant.
Repotting Hoya Australis shouldn’t frequently occur, no sooner than once every two years. Only consider repotting if the roots are visible above the soil. Hoya Australis does not take well to root disturbance. In fact, this houseplant likes a tight, root-bound root system. With more time, the roots will grow more compact. Repotting will disturb and loosen the root-bound growth. Soil aeration and sufficient drainage will help stimulate root health. Do not repot until necessary, which likely won’t be until after two or three years.
Hoya Australis Pests & Diseases
Because of its sweet sap and pleasant aroma, Hoya Australis can be susceptible to several pests. Mealybugs are the primary offenders, but aphids and spider mites are also common. Regularly checking your plant and wiping it clean will prevent any critters, and spraying neem oil onto the Hoya is a helpful and natural insecticide. Make sure to clean up any sap from cutting stems or leaves to avoid attracting insects, and keep the soil from getting too wet as bugs are also attracted to the moisture.
Creatures are not the only threat to the Hoya Australis. Root rot is a common problem caused by overwatering. Mold can also grow on the plant from excess sap remaining on the surface. You can easily avoid each issue by allowing the soil to dry sufficiently between waterings and cleaning any liquid that may extrude from the leaves or stems.
Where to Buy Hoya Australis?
Even though the Australis is one of Hoyas‘ most popular species, they are still relatively rare among houseplants. Though you are unlikely to find a Hoya Australis in the garden center of a home improvement store like Lowes or Home Depot, you may have better luck with a local nursery or garden. Etsy also has several options linked below! If you’re interested in other species of Hoya, the Hoya Carnosa is the most popular.
The Hoya Australis is an excellent houseplant for both the well-experienced and newcomers because of its general hardiness and beautiful appearance. Display this indoor plant on a tabletop or hanging basket to maximize its appeal. If you’re looking for a striking centerpiece, Hoya Australis can grow up to thirty feet tall when grown on a trellis! It will adapt to almost any environment and can survive a bit of neglect. But we think you’ll quickly fall in love and give it all the time and attention it needs!