Also known as wax plants, Hoya macrophylla have become very popular houseplants in recent years, and a lot of people want to know how to care for them more effectively. They are a great, low-maintenance plant with beautiful vines and tendrils that branch upward.
They can grow more than two meters tall, so if you’re looking for an impressive houseplant that has attractive flowers with sweet scents, this is perfect for you. The Hoya macrophylla is easy to look after and flowers from spring to late summer.
These plants are reasonably easy-going; once established in a suitable environment, they don’t need a lot of attention. They don’t require regular watering, and while they do need humidity, you can set up a system to keep this stable and the plant will grow happily without much further intervention.
Indoor vs Outdoor Growing
Hoya macrophylla plants come from Borneo and they enjoy tropical temperatures. If you want to grow one outdoors, you will need to live somewhere suitably warm. Otherwise, an indoor environment that is kept warm and humid will be needed in order for the plant to thrive.
That’s not to say you should keep your Hoya macrophylla on a radiator or other form of artificial heater, but the ambient temperature needs to be reasonably high if you want the plant to do well. It grows best between 65 and 80° F, and although it will tolerate temperatures as low as 55° F in the winter, it does better with hot temperatures.
It will grow in USDA zones 10 and 11; if you live in other zones, you will need to bring it indoors for the winter to protect it from cold weather. Many people like to grow Hoya macrophylla plants as houseplants so they can enjoy their beauty year round and not have to worry about the temperature outdoors.
Best Location For Your Hoya Macrophylla
A Hoya macrophylla likes to have plenty of light. It will grow in low light conditions, but very slowly, and it may be sickly and vulnerable to disease. It’s best to find it a bright spot. It can grow in any room in your house, provided there is enough light and space for it.
However, Hoya macrophylla plants are not fond of direct sunlight. They will tolerate a few hours of mild sun, but prolonged exposure or very hot sun in midsummer will burn the leaves and could kill the plant.
If you want to grow a Hoya macrophylla, it’s best to find an east or north-facing windowsill, where it will get bright but brief sunlight for a few hours each day. If your windows face south or west, you will need to position the plant further from them, or put up a net curtain to reduce the strength of the sun. Remember, the afternoon sun tends to be intense.
Other than light and space restrictions, you can grow your Hoya macrophylla anywhere in the house – bedroom, bathroom, office, living room – and it will bring a splash of greenery to the space.
Soil For A Hoya Macrophylla
Hoya macrophylla plants are epiphytes, and they like well-draining, loose soil that allows for plenty of air around their roots. They have a strong dislike for wet feet, so it’s important to make sure the soil is not heavy or sticky, but allows water to drain freely away from the plant.
Good aeration that will let oxygen surround the roots is also important. You should choose a rough growing medium that has plenty of structure and won’t end up compacting too much. Good drainage and good aeration are key to keeping this plant happy and healthy.
Next, the pH wants to be high. These plants come from naturally limey soil, so you need to make sure that the soil you are using is slightly alkaline, or at least neutral. The plant won’t thrive if you put it in an acidic growing medium.
Adding some crushed oyster shells or eggshells is a great way to increase the alkalinity of the soil and add a bit of structure and substance to it as well. You should use perlite in your container to help with drainage, and then a cactus mix and an orchid potting mix. Combining these three things in equal parts will ensure your plant has what it needs.
Don’t use an acidic soil in the pot, even if you have added lime; it is better to choose something that is naturally alkaline. Peat, therefore, is not a good choice for this plant’s growing medium, as it has a pH value of about 4.4 and this plant likes a pH value of around 6 or higher.
Watering Your Hoya Macrophylla
In their natural environment, Hoya macrophylla plants see rare but heavy rain. They often dry out completely and then get flooded by a rainstorm. They don’t get a sprinkle here and there every few days; it’s a bit “all or nothing” with this plant.
Simulating this environment for your Hoya macrophylla is a good idea, but it takes a bit of practice, especially if you are used to watering on a schedule. Instead of checking what day of the week it is, check whether the surface of the soil is dry.
If it is, press your finger into the pot and see if it feels dry beneath the surface too. Finally, tilt the pot and see if the drainage holes at the bottom are damp, or if they have also dried out.
If the plant is dry all over, it’s time to water it.
You can do a “deep watering” by standing your Hoya macrophylla in a bowl of water, and then watering from the top as well. This will ensure that the soil soaks up moisture at the bottom, but that the shallow-rooted plant also has access to plenty of water near the surface, where most of its roots are.
Thoroughly soak the pot and leave it for twenty minutes or so, and then allow it to drain. Your Hoya macrophylla has been watered, and shouldn’t need any further attention for quite a while. How often you need to do this will be very dependent on your climate, the pot size, and the potting medium you have used.
Don’t over-water your Hoya macrophylla. It will not like it, and it will probably die. Rare but thorough watering is the technique for keeping this plant happy, so let it dry out well before you water it.
Humidity For Your Hoya Macrophylla
These plants come from an extremely humid environment that you won’t be able to imitate in the standard home – and that’s probably the case even if you keep your Hoya macrophylla in the bathroom where it can enjoy the steam from a shower.
Unless you want to grow your Hoya macrophylla in a terrarium, there’s no point trying to emulate the 90% humidity that they usually grow in in the wild. Your home will probably suffer if you do! You’re also unlikely to be able to maintain this kind of moisture for any meaningful amount of time.
However, that doesn’t mean you should give up on trying to keep your plant damp and humid. It still needs plenty of moisture in its environment, and around 40% humidity is a good rule of thumb.
You should aim to mist it daily in the morning, and to be generous in this misting.
It is often best to use a spray bottle and spray the soil thoroughly, so that this moisture can evaporate over the course of the day, and rise up to humidify the leaves. Spraying the leaves themselves could lead to problems with fungus, especially if they remain wet overnight.
If you don’t want to humidify your plant manually, you have a couple of options. The first is to purchase a humidifier. This can be plugged in by the plant and switched on whenever you want to raise the humidity levels. You may also find it’s worth purchasing a hygrometer so you can keep an eye on how humid the air is.
A cheaper trick for humidifying is easy to make at home. All you need is a plastic tray with no holes in it and a small bag of pebbles.
Tip the pebbles into the tray, and then pour in some water, until the surface of the water sits just below the level of the pebbles. If you stand your plant on the pebbles, it will have constant humidity without getting wet feet.
Sometimes grouping Hoya macrophylla plants together can help to trap the humidity you make and keep it near the plants. The plants themselves will also produce some humidity. However, the problem with this is that they are a little prone to fungus, and crowded conditions can make this much worse.
Fertilizing Your Hoya Macrophylla
You can fertilize your Hoya macrophylla once a month or so when it’s in its growth season, but don’t overdo the fertilizer. It is best to dilute it heavily, often to half strength, to ensure the plant doesn’t get burned from over-feeding.
Fertilizing during the growing season can help to increase the speed with which the plant grows, but it isn’t necessary to do it as often as once a month unless you really want your plant to grow quickly. Topping up its nutrients occasionally is a good idea, but it is not essential to your plant’s survival.
Don’t fertilize the plant when it’s entering its dormancy period (winter) because it won’t get any benefit from the food then, and this will just sit in the soil and could damage the plant’s roots. Some people do continue adding a small amount of fertilizer throughout the winter period, but as the plant is not growing, there seem few advantages to doing this.
Instead, wait for the growth season to start and then give your plant the nutrients it needs to make the most of this season.
Hoya macrophylla plants are not toxic to cats, dogs, other animals, or people, but they should not be eaten. While they may not be actually dangerous, they could make anyone (or anything) that ingested them rather sick.
They are not considered edible, and consuming them may result in vomiting, choking, stomach ache, etc.
If you have pets that are keen to sample your plants or young children who are likely to pull off the pretty variegated leaves and try a bite, it may be best to grow your Hoya macrophylla out of reach. Try putting it behind a barrier, discouraging your pet/child from touching it, or moving it to another room where it is unlikely to tempt them.
If you suspect your child or pet has ingested any significant quantity of the plant, you should get medical advice. It may be nothing to worry about, but it’s better to be safe than sorry, so double-check with your doctor or vet.
Fortunately, Hoya macrophylla are very easy plants to propagate, so if you want to grow some more of them, you should have no problem doing so. You can collect, dry, and then plant the seeds if you choose to, but you can also propagate the plant by taking cuttings and replanting them.
If you have access to sphagnum moss, you may have more success in propagating the plant, as this is the best medium for propagation. However, if you don’t have this, you should still be able to successfully get cuttings to grow.
First, select a strong, healthy stem of the plant that does not contain any buds, but has a couple of root nodes and a few leaves. Sterilize your scissors/secateurs, and then cut the stem as close to the root node as possible without damaging it.
If you have some rooting hormone, you can dip the end of the cutting in this, but this isn’t necessary, so don’t worry if you haven’t got any.
You can then propagate your cutting in water or sphagnum moss. If you wish to use water, fill a clean jar with fresh water and allow the chlorine to evaporate off for a few hours. Next, put the cutting in the water and remember to refresh the water every few days. This stops it from stagnating and ensures there is oxygen available to the plant.
If you would like to use sphagnum moss, moisten the sphagnum moss thoroughly, and then put the cutting in. You can support it using a stick if necessary. Put a clear plastic bag over the top to trap moisture, and check on the cutting every few days. You will need to moisten the sphagnum moss if it dries out.
You can also do this with perlite, which has good oxygen flow, if you have any handy.
However you choose to propagate your plant, put it in a bright spot, but away from direct sunlight. Direct sun may burn the young plant and could cause it to dry out.
Your cutting should develop roots within a few weeks. If it doesn’t, you need to take a fresh cutting and try again. Once the roots are established, gently remove your cutting from its propagating medium and transfer it to some prepared soil. This can be tricky and is the point at which your cutting is most likely to die; the roots are not used to soil.
However, with care and luck, the cutting should take. Use soil that is similar to the mix described near the start of the article, ensuring plenty of drainage and aeration, or slightly increase the perlite for even better drainage.
Make sure your young plant does not get waterlogged; it will die quickly. It needs to be watered regularly, but only in small amounts, and only in the soil directly around the roots.
Treat young cuttings gently and don’t let them dry out a lot until they are established plants. As they grow, they can be treated more like adult plants and only watered when their growing medium is dry.
Depending on how often you fertilize it and its growth rate, your Hoya macrophylla will probably need repotting every couple of years. It is a shallow-rooted plant, so try and choose a shallow container, rather than a deep one. Deep containers can make it hard to tell when a plant needs watering, and offer no advantages.
The plant does not like being in a pot that is too big for it. It would rather be root bound than have too much space, so don’t repot it too readily. However, if you have used orchid mix as part of your growing medium, you will need to change the soil after a couple of years.
Once the orchid mix begins to break down, it will start to become acidic, and this could hurt the plant. It will also offer less and less structure and aeration as time passes. It is important to dispose of this and add fresh orchid compost to offer the structure and non-acidic advantages once more.
Make sure you have a container that will still provide a reasonably snug fit for your plant before repotting it, and reuse the same container if your plant has not yet outgrown it. There’s no reason to increase the pot size until the plant needs more space.
If you’re worried about your Hoya macrophylla, here are some common questions people ask, and our thoughts on whether there’s a problem and how to solve it.
What Pests Bother Hoya Macrophylla?
One of the commonest pests for this kind of plant is mealybugs. These little insects like damp, humid conditions and will infest your plant at the slightest opportunity. You should keep an eye out for little while balls on the undersides of the plant’s leaves; these are mealybugs.
They suck sap from your plant, stealing vital nutrients and causing the leaves to yellow and curl up.
If you find your plant has been infested with them, check all other plants in the vicinity too. Any that have been affected should be isolated from the non-infected plants, and then treated.
You can remove mealybugs by spraying the plant with neem oil; this will suffocate the insects. You need to make sure you spray the undersides of the leaves as well as the leaf surfaces.
You should keep the plants isolated and check them in a few days. You may need to repeat the treatment. Allowing the plant to dry out a little and improving its airflow should also help with the problem.
Aphids are another common pest, and will also suck your plant’s sap. They can be difficult to deal with because they can fly, so it’s easy for them to move from plant to plant. An application of neem oil will help to get rid of them, and soap and water can also kill them.
What Else Might Cause Yellow Leaves On My Hoya Macrophylla?
Yellow leaves can also be caused by fungal infections, which are especially common if your plant is in low light and has poor air circulation. You will need to relocate the plant, let it dry out a little, clean the leaves, and provide more airflow to address a fungal problem.
Over-watering is another common problem that can cause yellowed leaves, so check your plant’s soil is not damper than it should be, and if it is, cut back on the watering until it has dried out.
Why Is My Hoya Macrophylla Dying?
If your plant seems very unwell and you can’t detect visible problems on the surface, it’s possible that its roots are rotting due to over-watering. You need to gently lift the plant out of its pot and check whether it is getting waterlogged.
Mushy, soggy roots are a very bad sign. If you find them, you need to cut away all the damaged areas, leaving only healthy roots. You should then allow these to dry out while you prepare some fresh, well-draining soil for the plant. Discard all the old growing medium and start again.
Gently settle the roots into the new growing medium, and put the plant somewhere away from the sun while it recovers. Water it lightly for a while, and always check that it is drying out before you give it more to drink. Over-watering is a very common problem with houseplants, and your Hoya macrophylla will not appreciate it.