Everything about Hoya Genus

A Hoya plant has become increasingly popular as it can sprout pretty clusters of flowers and its waxy foliage looks fantastic in pots, hanging baskets, and even in terrariums.

Caring for a Hoya plant can be a daunting task but we’ve got you covered! Throughout this article, we’ll guide you every step of the way when it comes to caring for a thriving Hoya houseplant.

Main Characteristics

The Hoya genus has racked up quite a long list of common names such as wax plant, waxflower, Indian rope plant, porcelain flower, honey plant, and wax vine. It belongs to the Asclepiadaceae family which is also known as the milkweed family.

This tropical succulent is native to the warm and humid areas in Asia and Australia. It blooms stunning clusters of flowers that sprout from its woody stems. It is covered in glossy, oval-shaped leaves that grow on long vine-like stems.

A great benefit of growing a Hoya is that it’s an evergreen houseplant, just like the string of hearts plant. This means that you can expect its lush, emerald-green foliage to remain that color year-round and it won’t lose its leaves during the autumn or winter months.

Before we delve into the specific care requirements, let’s first take a look at the varieties and key characteristics of this houseplant.

Fun fact: The Hoya plant is named after a famous botanist in the 18th century called Thomas Hoy.

Types of Hoya

The Hoya genus has tons of species and variations, and we’ll be discussing the top 15 most popular ones.

• Hoya archboldiana: It has bell-shaped flowers that are a creamy white and maroon red color. This houseplant grows fairly sturdy, hard, and dark green leaves.
• Hoya australis: This is called the ‘common wax flower’ and it grows slender, long stems that are covered in oval, glossy leaves.
• Hoya bilobata: This houseplant is regarded as one of the more fussy Hoya species. It can grow a slender, vine that blooms tiny, bright red flowers with a pleasant fragrance.
• Hoya burtoniae: This specific Hoya houseplant is native to the Philipines, and its foliage has a soft, fuzzy appearance. The leaves are an olive-green color with a red ring along the leaves’ edges.
• Hoya callistophylla: This is a great plant for a beginner as it is known to be very disease resistant and its light green leaves have intricate dark veins.
• Hoya carnosa: It is one of the most common Hoya varieties because of its lush appearance. It grows oval-shaped, bright green leaves and it regularly sprouts beautiful pink-purple flowers.
• Hoya cumingiana: This variation is commonly called the ‘Hoya aloha’ and ‘fung wax flower’. Its olive-green leaves have gorgeous gray variegation.
• Hoya curtisii: It has a bushy appearance as the vibrant green, waxy foliage grows closely together.
• Hoya kalimantan: The houseplant has lime-green leaves with dark green veins. It produces tiny, bright yellow flowers with maroon-colored tips.
• Hoya kerrii: The ‘sweetheart plant’ is often bought as a single leaf. This green, thick and waxy leaf takes on the form of a heart hence its nickname.
• Hoya linearis: It takes on a curtain-like form as its long leaves cascade over the pot’s edge. Its leaves also have tiny hair-like structures that give it an overall fuzzy look.
• Hoya macrophylla: This variation has sturdy, dark green foliage which is framed by a yellow-green border.
• Hoya shepherdii: It’s also known as a ‘string bean’ Hoya because of its elongated, smooth leaves. The houseplant typically doesn’t grow very tall but its flat leaves look great in a hanging basket as they fall over the edge.
• Hoya obovata: It is classified as a semi-succulent and it has long tendrils and light green oval leaves with thick veins.
• Hoya wayetii: This type has tough, hard, green, and elongated leaves with a brown-red frame along the leaves’ edges.

Fun fact: The Hoya is said to be made of approximately 900 different species.

How Big Does It Get?

A typical Hoya plant can grow up to 2 to 4 feet (0.6 – 1.2m) tall. Its leaves are what really grow long as they can reach up to 12 to 20 feet (3.6 – 6.1m) in length.

How Fast Does It Grow?

The exact growth rate differs across the various types of Hoya but an average wax vine can sprout 4 to 10 inches (10 – 25cm) of new growth each growing season.

The houseplant won’t produce any new growth during the winter and the less light it receives the slower its rate of growth will be.

Lifespan

The average waxflower can survive for roughly 10 to 15 years when cared for well.

Some expert houseplant cultivators have succeeded in growing their own Hoya for up to 30 years, however, this will take a great amount of precise care.

Is It Toxic to Cats, Dogs and Humans?

The stunning Hoya is non-toxic. This means it’s perfectly safe for cats, dogs, and children should they come into contact with the houseplant.

If you want to keep any wandering hands or curious pets away from the plant then grow it in a hanging basket so that it’s out of reach.

Hoya Plant Care

Our care guide is full of top tips and tricks to growing a prosperous Hoya. We’ll discuss the precise care that your Hoya houseplant requires.

How Often to Water It

The wax vine requires a good watering as it is a thirsty houseplant, much like the Calathea. The most important thing to remember is that you must allow its soil to dry out in between waterings.

During the spring and summertime, you can water it once or twice a week. Once it’s cooler in autumn and winter then you should water it once every two weeks.

It is best to water it with room temperature water as if it is too cold then it may shock the root system. Additionally, you must allow the excess water to drain out the holes at the bottom of the container.

Top tip: Water a flowering Hoya more often as it’s particularly thirsty when it blooms.

Drainage

A wax plant should be grown in well-draining soil and a pot with drainage holes. Good drainage and excellent circulation are imperative for its survival, and the same can be said for many other houseplants such as the Hibiscus.

A soggy environment will not only cause root rot but it may lead to several fungal diseases too.

How to Prune It

A porcelain flower requires vigorous pruning during the spring. You may need to trim back black, brown, or dry foliage and it’s best to snip off any leggy vines to keep the growth compact.

Keep in mind that you don’t want to cut back any leafless stems as this is where flowers sprout from. When they’re removed it may take longer for your plant to bloom in the future.

While pruning you should be wary to not remove too many stems or leaves. Ideally, you should never prune off more than one-third of the houseplant at a time.

Follow these three steps below:

1. Sterilize your scissors/pruners and begin cutting the lower-level vines.
2. Work your way up and remove any unhealthy growth.
3. Water your houseplant well and place it back in its sunny home.

Fun fact: The leafless stems are known as ‘spurs’, and are vital for a plant to bloom.

Repotting

It is preferable to repot the houseplant during the springtime every 2 to 3 years, as it loves to be slightly pot bound. If you rush to repot your plant then it may not bloom. It should only be transplanted when the roots begin to grow out through the drainage holes.

The new container should be about 2 inches (5cm) wider than its current pot. A container that is too big will cause root rot.

Stick to the steps below to successfully repot your houseplant:

1. Water it deeply at least one day before you repot it.
2. Loosen the soil by sliding a blunt knife around the edge of the pot, and then remove the rootball.
3. Shake the rootball to remove the extra soil surrounding the roots.
4. Fill a new container with fresh potting mix and plant the Hoya as deep as it was previously planted.
5. Give the houseplant a good watering and place it back in its original position.

Top tip: Avoid repotting the Hoya while it’s blooming or the buds may fall off.

Environment Conditions

Light Requirements

The wax plant flourishes in bright, indirect sunlight. It should be placed in an area where it’ll receive around 10 hours of sunshine a day.

The houseplant can tolerate a low-lit area but it won’t bloom or sprout new growth. On the other hand, if it receives direct sunlight then its leaves may burn and the variegation and color of the leaves will begin to fade.

Top tip: A bright windowsill or patio is the perfect spot for this houseplant.

Best Soil Mix

A porcelain flower must be planted in light, well-draining, and loose soil. It cannot withstand a heavy potting mixture as this will retain too much moisture and become saturated.

The soil should have a pH level between 6.1 to 7.5. To create the ideal potting mixture, you can add in a handful of perlite to enhance its aeration and drainage.

The following potting mixtures are great for a Hoya plant:

• Cacti potting mix
• Orchid potting mix
• African violet soil

You can even mix together 2 parts sphagnum moss and 1 part perlite for the optimum soil.

Fertilizer

A wax plant should be fed once a month during spring, summer, and autumn. It needs the most nutrients and minerals while it is actively growing.

Ideally, the fertilizer must contain all three minerals; nitrogen, phosphorus, and potassium. The optimal fertilizer is one that is high in potassium because this will encourage growth and flowering.

Choose a well-balanced, liquid fertilizer. Before you feed the houseplant, you must dilute the fertilizer to half its strength.

Pot Size and Type

The waxflower isn’t too fussy when it comes to the type of pot it’s grown in, as long as it has drainage holes. Your general plastic container will do just fine.

The houseplant doesn’t need a big container as it prefers to be slightly pot bound. It loves to live cozily in a pot that is around 1 to 2 inches (2.5 – 5cm) wider than its rootball.

Temperature Tolerance

A wax vine thrives in a warm climate. The ideal environment is one with a temperature range of  65 to 75°F (18 – 24°C).

The temperature should never dip below 60°F (16°C) when grown indoors and make sure that it isn’t kept near a cold draft or vent.

Humidity Level

Just like the Cyclamen, this houseplant loves a humid climate. The porcelain flower is native to humid tropical regions and it needs to be located in humid surroundings as a houseplant too. The relative humidity level should never drop below 50 percent.

The optimum level of humidity is above 60 percent and there are a few ways that you can create this.

We’ll list three methods below:

• Mist the plant with room temperature water, but make sure to avoid spritzing the flowers.
• Put a humidifier near the houseplant.
• Build a humidity tray by putting some gravel/pebbles in a shallow tray and pouring some water inside it. You can then place the pot on top of the pebbles.

Outdoors vs. Indoors

The wax plant can be grown outdoors in USDA hardiness zones of 8 through 11. It is native to tropical regions so if you plan on growing it outside then make sure that you can recreate a tropical, humid and sunny environment in your garden too.

It prefers non-direct sunlight as full sunshine will scorch its leaves. If you want to encourage blooms then mist it frequently as it’ll require high humidity levels when grown outside.

The temperatures should never fall below 20°F (-6.7°C) as it cannot withstand frost.

Flowering

Sadly, the houseplant rarely blooms when grown indoors. If you’re lucky to grow a plant that blooms then it may sprout flowers in an array of colors like red, pink, white, orange, black, yellow, and purple. The color is also dependent on the species too.

Typically, the Hoya plant will sprout clusters of 40 individual flowers throughout late spring to early autumn. The precise time of blooms will differ from species to species.

The cup-shaped blossoms will usually last for about 3 to 4 weeks before dying off. When the flowers begin to die or their color starts to fade then you should snip them off straight away.

How to Get It to Bloom

You can encourage it to flower by making sure that it receives as much bright light as possible and that it’s grown in a humid environment.

How to Grow It

You are able to grow more waxflowers by propagating it or planting its seeds. You can carry out each one of the methods below during the spring or summertime.

If you propagate it or plant its seeds during the winter then it is unlikely to develop new root growth or germinate.

Hoya Propagation

A porcelain flower can be propagated in water and soil. We’ll explore each method of propagation below and guide you through the entire process.

Before you plan on propagating a plant, make sure that your current houseplant is healthy. You don’t want to use unhealthy cuttings or divisions as these won’t successfully propagate and you may damage the mother plant.

Propagating in Soil

You can propagate a Hoya by planting its stem cuttings, leaf cuttings, layering, or divisions in quick-draining soil. Always clean your tools with a diluted bleach solution to prevent spreading bacteria from one plant to the other.

How to Root Its Cuttings

Stem Cuttings

Propagating a stem cutting in some soil is one of the easiest and most successful methods to grow a Hoya. We’ll explain how to cut the stem and how to plant it.

1. You can cut a 4 inch (10cm) long stem and apply rooting hormone to the cut end.
2. Pluck off any leaves that may become covered by soil, and plant the cutting in a rich potting mixture.
3. Water the cutting lightly and position it under bright sunlight.
4. After a month the roots will have grown and established themselves.
5. You can then care for this plant as you normally would.

Leaf Cuttings

It is rather tedious and time-consuming to propagate a leaflet and it isn’t always successful either. We’ll guide you through the entire process to enhance your chances of success.

1. Cut a few leaves and dip each cut end in rooting hormone.
2. Plant the tips of leaves in some soil at a 45° angle, and keep the potting mixture moist.
3. It is best to locate the cuttings in indirect sunshine.
4. It should take 5 weeks before new roots begin to grow.
5. You can repot the cuttings once they’re large enough and require their own container.

Layering

Layering the Hoya is a very easy way to multiply your collection, and you don’t even have to snip off its stems or leaves.

Here’s a step-by-step guide to layering a waxflower:

1. First, fill a new pot with moist soil.
2. Place this pot close to the Hoya and position a vine on top of the potting mix. You can even use a floral pin to secure the stem to the soil.
3. Make sure to regularly water the plant and keep the soil moist.
4. Roots will begin to grow on top of the soil, and you can then snip off the vine so that it’s no longer attached to the mother plant.
5. Care for the plant as you would a mature houseplant.

Propagating By Division

Dividing the waxflower’s rootball may be a little messy but it is a pretty straightforward process too. All you have to do is separate the rootball and plant the divisions. We’ll explain the process more in-depth below.

1. Remove the plant from its current container and brush off the soil surrounding the rootball.
2. Slice the rootball into different sections and gently pull these divisions apart.
3. Plant each division in a new pot with well-draining soil and water them.
4. Locate the divisions in a sunny home and care for them as you did their mother plant.

Propagation in Water

You can propagate the stem or leaf cuttings in distilled, tepid water. The most important consideration is that the water must be clean, so you may need to replace it every 2 or 3 days.

Propagating them in water is a great way to monitor root growth and check that your cutting is healthy.

Growing from Stem Cuttings in Water

You can grow an entirely new plant by simply snipping off a healthy stem and placing it in some water. The following guide will take you through each step.

1. Snip off a stem that is around 4 inches (10cm) long and dip the cut area in the rooting hormone.
2. Remove any leaves close to the cut end so that they don’t become submerged in the water.
3. Fill a glass with room temperature water and place the cutting inside.
4. It will take over a month before the stem sprouts roots. Once it does you can repot it in a fresh potting mixture.

Growing from Leaf Cuttings in Water

A leaf can be plucked and grown in a small glass of water before repotting them in soil. We’ll list the steps below.

1. Pick off 2 or 3 leaves and dip the cut end in some rooting hormone.
2. Fill small glass jars with water and place one leaf inside each of them. Make sure that only the tip of the leaf is submerged in the water.
3. Place the leaflets under indirect sunshine and switch out the water every few days.
4. You will need to wait for 5 or 6 weeks before any new growth sprouts.
5. Once an inch (2.5cm) of new root growth has developed, then repot the cuttings in soil.

Seed Planting

The wax vine can be grown from seed but it isn’t a highly recommended or successful method. If you’re up for the challenge then purchase some Hoya seeds, get out a tray, plastic bag, and seed-starting potting mixture.

Follow the steps below:

1. Fill a tray with the potting mixture and moisten it.
2. Press the seeds into the soil and make sure they’re about 2 inches (5cm) apart from one another.
3. Spritz them and place a clear plastic bag over the tray.
4. Find a sunny home for the seeds and keep the soil moist at all times.
5. The seeds should germinate in about 7 to 10 days, and once new growth emerges then you may remove the plastic bag.
6. Care for the seeds well and repot them once they sprout three leaves.

How to Save a Dying Plant

A Hoya plant is relatively hardy and is resistant to diseases, however, it can suffer from certain fungal infections or run into a few issues if it receives improper care.

Below, we will explore each potential problem that your houseplant may be facing and we’ll tell you what to do to revive your plant back to health.

Root Rot

Overwatering the wax plant for an extended period of time will cause root rot. The vines will become droopy and the mushy roots will turn into a black color.

You must act fast and the best way to solve this issue is by repotting the plant immediately. You must cut off any dead or dying roots and plant it in new, dry soil. You should allow the roots some time to recover and water it after 5 days.

Fungal Leaf Spot

Your wax vine is suffering from fungal leaf spot when small black dots begin to appear on its foliage. This is caused by a bacterial infection and overwatering it.

The most ideal way to resolve the problem is by allowing the soil some time to dry before watering it again.

Why Are the Leaves Turning Yellow?

When a porcelain flower’s foliage begins to yellow then it is either being overwatered, underwatered, placed in direct sunshine, or it’s overfed.

All you have to do is make a slight adjustment to your overall care regime.

The best way to determine the exact cause of the problem is by examining the soil. If the potting mixture is wet then you need to refrain from watering the plant until the soil has completely dried out. When the soil is too dry then you need to water the plant thoroughly.

During the summertime, the plant cannot withstand full sunshine. You will need to find a bright area where it’ll soak in some non-direct sun.

A fertilizer overdose is caused by frequent feeding or using a strong fertilizer. You must flush out the salts from the soil by placing it under a stream of water for around 10 to 15 minutes. Additionally, you must always make sure to dilute the fertilizer before using it.

Grey Mold

If your Hoya houseplant leaves become squishy, sloppy, and develop grey edges then it’s suffering from a fungal infection. It is called Botrytis cinerea and is more commonly known as grey mold.

Last Remarks

The Hoya is a great houseplant to grow in your home. It has vibrant, lush foliage and you can gather quite a large collection by growing the many variations. It may require specific care but its cascading and waxy appearance is well worth the effort.