Hoya Australis | Plant Care Guide

hoya australis

If you are looking for a house plant that combines beautiful foliage and fragrant flowers, hoya  australis is the plant for you. As a vining plant, owners love to train this plant to climb up different shaped trellises.

This is a great plant for beginners because it is very forgiving of any missteps. As a bonus, it is also great for air purification.

Botanical NameHoya australis
Common NameHoney Plant, Porcelain Flower, Wax Flower, Wax Plant, Waxvine
Size13-33 feet
DifficultyEasy
Pet FriendlyYes, Non-Toxic
Air CleanerYes

Hoya Australis Origin

Hoya australis is a member of the Apocynaceae family. It is also known as the wax vine, honey plant, or the porcelain flower. This tropical plant is native to Australia and was first discovered by Europeans in 1770. 

How to Care for Hoya Australis

This plant is more forgiving than many plants and can survive in most conditions. However, it does have preferences which result in optimal health and a beautiful plant. 

Light and Temperature

As a tropical plant, hoya australis prefers a warm environment. However, some varieties of wild hoya australis grow at high altitudes with cold nights, so they can handle a variety of temperatures. 65-75 degrees Fahrenheit is a nice moderate temperature range to aim for. It is recommended to prevent any extreme temperatures (hot or cold) and avoid any major temperature swings. 

In the wild, hoya australis typically grows in forested areas under a canopy with filtered light. Indoors, it is best to replicate these conditions by placing your plant in a location where it receives bright, indirect light. Hoya australis will enjoy a small amount of direct sunlight in the early morning or late afternoon, when the sunlight is not as strong. 

Hoya australis can grow under artificial light so it is a good option as an office plant. However, in order to flower, this plant requires medium or bright light. 

Soil and Container

One of the most interesting ways to display hoya australis is to train it to climb on a trellis. You could use a traditional trellis or a more interesting shape, like a circle or heart.

If you would like your hoya australis to trail down, you could plant it in a hanging basket. To train your plant to climb around window or door frames, use adhesive plant clips that will secure your vine without damaging it. 

Since this plant is not as particular with conditions, almost any container will work for it. However, it is recommended that all house plants are housed in pots with drainage holes so that you can control the amount of moisture in the soil.

Hoya australis grows as an epiphyte (on another plant or rocks instead of in soil) in many locations. Roots of this nature like to have aerated soil which is easy for the roots to grow through. It is also important that the soil drains well to prevent overwatering and root rot.

A combination that works well for hoya australis is one part compost, one part orchid bark, and one part perlite. Any aerating material, such as perlite, charcoal, or pine bark, is recommended to be included in your soil mix.

Water and Humidity 

Hoya australis has low to moderate water needs. For most conditions, this means it needs to be watered approximately every 10 days. More importantly, you should only water your plant when the top half of the soil is dry to the touch. 

The leaves of your hoya australis will let you know if it is receiving too much or too little water. Yellowing leaves that are starting to drop are a sign of overwatering. Crinkled leaves that are dry are a sign of under watering. Adjust your watering schedule accordingly. 

When watering, fully saturate the soil until excess water is draining from the bottom. Allow the pot to fully drain and remove excess water from the saucer. Hoya australis can be sensitive to hard water. If your area is known to have hard water, it is recommended to use rainwater or filtered water for your plant. 

Hoya australis enjoys moderate to high humidity and it is recommended to maintain ambient humidity of at least 40%. This plant responds well to being placed over a pebble tray, but a humidifier can be used if you are in a dry climate. 

If you are trying to promote growth and blooming, your plant may do better with higher humidity. However, high humidity can come with challenges, such as pests and fungus. Leave space around your hoya australis and make sure there is good air flow to help prevent these issues. 

Fertilization

This plant is a light feeder so it is important to not over-fertilize. Dilute your fertilizer to half the recommended dose. Use a balanced or bloom fertilizer once per month in the spring and summer (and fall, if you live in a warm environment). Do not fertilize in the winter because the plant is barely growing or not growing at all.

Flowering

With the right conditions, hoya australis can produce flower clusters in summer with a sweet vanilla scent. These flowers are small, white, and star-shaped. They have red centers. The sticky nectar that drips from the flowers can damage furniture, so place your plant accordingly. 

Your hoya australis will only bloom if all of its needs are being met. Most importantly, it needs to be receiving adequate lighting. If your plant is not blooming but is healthy, try moving it closer to a window where it will receive brighter light. 

Pruning

Hoya australis does not need to be pruned to maintain the health of the plant. However, many people will trim the long vines to control the same. Since the vines can grow over 9 feet long, they can get out of control if left untrimmed. 

Spring is the best time to prune so new growth can come out during the growing season. Blooms will typically come from new growth, so if you are looking for flowers, only prune older vines. Pruning can also be used to create a bushier plant that does not trail out of the planter. 

Repotting

Like most hoya species, hoya australis does better when it is root bound. This plant can also suffer shock after repotting, so it is important to do it carefully. Spring is the best time to replant because it allows the roots to re-establish during the best time of year. Include plenty of pumice or perlite in your soil mix to create aeration and give the roots space to grow into. 

Pests

Due to the succulent nature of hoya leaves, they can be susceptible to a variety of sap-sucking pests, including mealybugs, whiteflies, and scale. 

Mealybugs are white, fluffy insects that are commonly found on new growth and where leaves attach to the stem. They can reproduce quickly and cause serious damage to the plant if left untreated.

Whiteflies are most common in summer and congregate on the underside of leaves. They are small, white flies that can be seen flying around the plant. Sticky traps placed near the plant can help catch adults, but the eggs and larvae will still need to be treated. 

Scale insects are similar to mealybugs. However, they have hard brown exteriors and do not move once they find a location to feed off the plant. 

Larger individual pests can be killed using a cotton swab dipped in alcohol. However, it is important to treat the entire plant as well to remove all eggs and larvae. For any sap-sucking insects, a gentle shower can remove most of the population. Follow up the shower with regular treatments of neem oil or an insecticidal soap until you are confident the infestation has been thoroughly treated. 

To prevent these pests, never overwater your hoya australis or allow water to sit in the saucer. Airflow around the plant is also important to discourage too much humidity and moisture in the environment. Isolate any plants with a pest infestation to make sure it does not spread to other plants. 

Diseases

The most common diseases that affect hoya australis are fungal infections, since this plant enjoys higher humidity levels. Maintaining airflow around the plant can help prevent fungal infections from taking hold, even with high humidity. 

Fungal root rot is a common disease for plants that are being overwatered or have soil that holds more water than the plant can use. Unfortunately, most people do not discover root rot until it is too late. Your hoya australis will start to look limp and the base of the stem will become mushy. These advanced infections can be hard to treat. 

If any healthy parts of the plant are able to be saved or if cuttings are taken, replant the hoya australis in a brand new pot with pasteurized soil. Prior to replanting, rinse off any remaining roots thoroughly. Take care to only water enough to allow the roots to re-establish. 

How to Propagate Hoya Australis 

Since hoya australis can bloom indoors under proper conditions, one of the best ways to propagate new plants is to collect seeds. Be advised that not all blooms will result in seed pods. Hoya australis has a unique flower structure and the pollen is contained in small sacs that need to be pierced (typically by insect legs) to release the pollen. Some people have had success self-pollinating their plants using a cat whisker or thin needle. 

Once a seed pod has formed, allow it to dry out. You can then collect the seeds inside. These seeds will not keep for too long, so it is better to plant them as soon as possible to ensure germination.

In addition to seed collection, stem cuttings can also be used to propagate new plants. Find a non-flowering stem with at least two nodes (found below leaf attachments). Always use sterilized scissors or garden shears when taking cuttings.

To propagate your cutting in soil, use a mixture of mostly perlite or pumice with some organic material. Creating a small greenhouse using a plastic bag over the pot will help keep the soil moist and keep the humidity high. Roots should form within a month.

To propagate your cutting in water, use filtered water and place your cutting in a bright, warm location. Roots should begin to form within a couple of weeks. Once the roots are a few inches long, transfer the cutting to soil. Keep the soil moist and humidity high for a couple of weeks to promote root growth.

Frequently Asked Questions

Hoya australis is a fast-growing plant and can grow vines over 9 feet long. To promote fast growth, keep your plant in a bright location with high humidity. 

The most important factor to get your hoya australis to bloom is adequate lighting. Make sure your plant is receiving bright, indirect light at a minimum. If it is still not blooming, find a location that allows your plant to receive direct sunlight in the early morning or late afternoon.

In addition to plenty of sunlight, some hoya australis plants prefer cooler overnight temperatures and cold winters in order to put out blooms.

Yes, hoya australis is toxic to pets and kids. The sap from the plant contains latex, which is toxic if ingested and irritating to the skin.

Final Thoughts on Hoya Australis

With many unique hoya plants to choose from, you might be having trouble deciding which one to purchase. Hoya australis should be your top choice because a vining plant wrapped around a trellis with fragrant flowers is a one-of-a-kind houseplant.

Be sure to check out all of our Plant Care Guides!

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