With approximately 300 species and subspecies of tropical Hoya plants out there, it’s no surprise that Hoya australis would have some of its own.
Hoya australis (HOY-a aw-STRAL-iss), like its relatives, is a member of the Apocynaceae family.
Australis Hoya includes five subspecies and at least five cultivars originating in various parts of the continent, including Bathurst Island, Kimberly, New South Wales, Papua New Guinea, and Queensland.
The subspecies are:
- H. australis oramicola
- H. australis rupicola
- H. australis sana
- H. australis sanae
- H. australis tenuipes
While this plant shares the common name of wax plant with the rest of its genus, it is also known as:
- Honey Plant
- Porcelain Flower
- Wax Flower
Hoya australis is the second most popular species of hoya plant after Hoya carnosa.
These perennial evergreens are becoming common sights as a air-purifying house plant.
One of the things which makes the plant so popular in today’s busy world is the fact that you don’t have to know how to care for Hoya australis beyond a few basic guidelines since it practically takes care of itself once set up.
Hoya Australis Care Tips
Size & Growth
While there is some variation between subspecies, the wax plant is a climbing vine that generally achieves a height of 13′ to 33′ feet.
Its green leaves are shiny, lending to the common name, and are both succulent and either elliptical or oval.
Depending on the amount of light, the leaves vary between dark green and yellowish-green.
Flowering and Fragrance
The honey plant gets this particular nickname because Hoya australis is one of the species which have fragrant flowers.
The star-shaped blooms of this species are creamy-white with burgundy centers and produce a large amount of nectar that may drip.
These 5/8 to 1″ inch diameter flowers are in clusters atop ⅜ to 1″ inch long peduncles.
Blooms occur during summer and may be adversely affected by recent pruning or low light levels.
The heady scent resembles a chocolate-vanilla aroma and is most noticeable in the evening.
Long, slender seed pods approximately 4″ inches long follow the flowers and are easily harvested while pruning.
Light & Temperature
Wax plant prefers bright, indirect light, but it offers an interesting benefit to choosing different light levels.
When exposed to more light, the plant’s leaves will turn a yellowish-green, while leaves kept in partial shade will become dark green.
This variation can happen on a single plant when one side has more light exposure than the other, or you can move the plant to a spot that will give you a foliage color you prefer.
Note that the plant will thrive under fluorescent lighting but will burn in direct sunlight and may not bloom in full shade.
Hoya australis can be grown outdoors in USDA hardiness zones 10a to 11b, although it’s best to bring it inside if the temperature drops below 55° degrees Fahrenheit.
Indoors, it is most comfortable when the temperatures range between 65 and 75° degrees Fahrenheit.
A humidity level between 40 and 60% percent is preferable.
Watering and Feeding
Porcelain flower doesn’t need much water, as the succulent leaves will hold some in reserve.
As a general rule, water every 10 days or when the soil’s dry to 1 or 2″ inches deep.
Avoid overwatering as this may lead to root rot.
Using a hydrogen peroxide mix will not only mimic natural rainwater, it can help reduce the risk of developing root rot.
Reduce watering in the winter.
During the summer months, treat your Hoya plant to ¼ teaspoon of a balanced, general-purpose fertilizer in 1 gallon of water every 30 days.
Soil & Transplanting
A well-draining soil is essential for a healthy Hoya plant.
You can make your own or add perlite or pine bark to a loamy potting mix.
Unlike most houseplants, Hoyas prefer being root-bound, so you should only transplant or repot when absolutely necessary.
Grooming And Maintenance
Your wax plant will need proper support, such as a trellis.
It can be pruned after flowering is over or during the spring to maintain a manageable height.
Pruning too close to bloom time may reduce the number of blooms, as buds generally arise from new growth.
More On The Hoya Topic:
How To Propagate Waxvine
The easiest method of propagation is via cuttings and may be performed in either water or soil.
In both cases, select a non-flowering stem and ensure your clipping contains at least two nodes.
- Mix 3 parts perlite
- 1 part coconut coir or peat
- Dip the end of the cutting into rooting hormone
- Place the cutting in the potting medium
- Cover the pot and cutting with a plastic cover to keep in humidity.
- Keep the temperatures of 70° degrees Fahrenheit or more.
- Roots will generally take one month to begin growing.
- Fill a propagation container with distilled water
- Add a few drops of liquid rooting hormone
- Insert the cutting at a node.
- Root buds should appear in about 2-3 weeks.
- Repot in soil once the roots have grown to a few inches
- Keep the soil moist for the first week.
Wax Flower Pests or Diseases
While Hoya plants are generally considered pet friendly by the ASPCA, there is some concern the sap may cause irritation or allergic reactions due to the presence of natural latex.
Learn More: Hoya Plants – Are They Poisonous?
Mealybugs, spider mites, and whiteflies are all common pests that prey on hoya species.
Hoya australis is drought tolerant and can withstand brief exposure to frost, although it is not frost hardy.
Root rot is a common problem when this plant has been overwatered.
Suggested Hoya australis Uses
The wonderful fragrance and glossy leaves of this plant make it a great addition to both gardens and homes.
Its vines will cling onto any surface, but trellises work best for guiding the plant.
The air-purifying qualities and wonderful aroma of its flowers make this an ideal indoor plant.
Additionally, it’s a great choice for offices due to its ability to thrive under fluorescent lighting.