Hoya Merrillii Care – Light, Water, Soil, Propagation, Repotting

Last Updated on March 19, 2022 by Admin

The Hoya Merrillii is a beautiful vining plant that features stunning leaves and fragrant flowers. This makes it a good choice if you like to have both.

The plant used to be very inexpensive. Although, as it has become more popular like many hoyas have, its prices has gone up quite a bit. Still, I do recommend picking up if you find one.

One thing I love about this plant is if you give it bright light, its leaves will turn bush red, making it look even more beautiful. You can get this by adjusting how much sun it gets or supplement that with LED grow lights.

The Hoya Merrillii is native to the Philippines.

How do you care for Hoya Merrillii? Give the plant bright, indirect light. If you want to make its leaves blush and turn a bit reddish, high light will do the trick.

Keep the plant in cool to moderated temperatures with high humidity (>60%). It also needs fertilizer and you can switch to orchid food to help it bloom.

Finally, avoid overwatering and use well-draining soil.

Hoya Merrillii Plant Care

Light Requirements

The Hoya Merrillii is best kept in bright, indirect light. This will allow it to grow optimally and produce lush foliage.

That said, it will also do very well in medium light and tolerate low light to a certain degree. But I don’t suggest leaving it in low light conditions as this will reduce the likelihood of the plant flowering.

Instead, it needs a well-lit location to bloom.

Similarly, while the Hoya Merrillii can withstand direct sunlight, it can only take about 2 hours or so of this a day.

If it stays there longer, you’ll see its leaves get discolored. And worse, they can get scorched leaving you with brown burn marks on foliage.



The Hoya Merrillii likes a fairly cool environment. Its lead temperature is between 40 to 50 degrees Fahrenheit.

Although, because it is a native of the Philippines, it will easily tolerate warm weather as well. Therefore, the plant can withstand climates up to 90 degrees without any issues.

Like other hoyas, you can keep the plant indoors or outdoors.

But if given a choice, it will do better indoors since the conditions will stay more consistent. The protected environment will also allow it to have a longer, healthier lifespan.

As far as zones go, it is best suited for USDA Hardiness Zones 10 and 11.



The Hoya Merrillii prefers humidity of 60% or higher.

Again, this comes from its native environment where the weather is consistently warm and humid all year round.

As such, if you want the plant grow fast and produce vibrant leaves, keep it in this humidity.

While it can tolerate lower levels, you do want to monitor how it responds there.

That’s because the lower the humidity goes, the more likely it will experience brown and crispy leaf edges and tips. This is a sign that the air is too dry and you need to help it out.

The fastest way to fix this is to move the plant to a location with higher humidity.

In homes, the bathroom and kitchen often have more moisture in the air and vapor because we tend to use water in these areas.

Another option to get a humidifier.

If you don’t want to spend money, you can either mist the plant 2-3 times a week or use a pebble tray.




How Often to Water Hoya Merrillii

The Hoya Merrillii needs moderate watering. It prefers soil to stay moist but not wet.

Therefore, it is a good idea to wait until the soil dries before adding more water. You want to be very careful about adding water while the soil is still wet since the plant is prone to overwatering.

At the minimum, I suggest waiting until the top 2 inches of soil has dried before watering it again. This will ensure that you don’t end up giving the plant too much water.

It is also important to remember to adjust your watering routine as the weather changes though the year.

In the summer, you will need to water more often because there is more sun, and the temperature is hotter. This will cause the soil to dry much faster.

In the winter, the opposite is true. The cold weather and decreased sunlight will keep the soil wet longer. This means it is essential to avoid following the same schedule as you do during summer.

Instead, wait until the soil dries out more before watering again.

Too much water not only increases the possibility of bacterial and fungal infections, it also puts the plant  at risk of root rot.

Therefore, watering is something you want to be mindful of.


Hoya Merrillii Potting Soil

The Hoya Merrillii is not choosy when it comes to potting soil. in fact, it will do well with standard houseplant potting soil. However, for the best results, it is a good idea to add perlite to improve drainage.

This will ensure that excess moisture will quickly drain, which reduces the risk for overwatering.

This also gives you some leeway in case you happen o overwater the plant at times. The soil will help you out by getting rid of excess moisture so the roots don’t end up sitting in water.

As far as soil pH goes, the Hoya Merrillii will do best between 6.1 and 7.5. This is slightly acidic to neutral pH).

From experience, the best soil for this plant is light, airy and well-draining. And you can use this combination of ingredients to create your Hoya Merrillii potting soil at home.

  • 1/3 cactus mix
  • 1/3 perlite
  • 1/3 orchid mix

You can also replace the cactus mix with potting mix if you already have some at home.

The perlite increases drainage so that the blend can get rid of excess water in the soil to avoid waterlogging.



The Hoya Merrillii does not require a lot of fertilizer. However, it needs fertilizer to grow healthy and avoid nutrient deficiencies.

This means that you want to apply fertilizer. But be on the more conservative side.

That is avoid overfeeding the plant.

You can use a balanced, liquid fertilizer diluted to half or quarter strength during its growing season. There is no need to feed the plant during winter.

That said, it like to help the plant out so it can flower.

Thus, when you see the plant about to bloom or is blooming, switch to orchid fertilizer or one with a higher phosphorus ratio.

This will help with blooming and sustaining the blossoms longer.



As with other hoya varieties, the Hoya Merrillii produces beautiful blooms. These are white-yellow in color.

Each individual flower is tiny, but they tend to grow in clusters shaped like spheres. This makes them visually stunning.

The best way to encourage your Hoya Merrillii is to give it sufficient light. This is why bright, indirect light is ideal when choosing a location for the plant.

It is also why the plant usually flowers during spring and summer.



The Hoya Merrillii can grow to as long as 6-8 feet. Although despite its length, it will not be as imposing or as impressive as a monstera or philodendron in size because its length is largely made up of its vines.

This makes it beautiful and makes the plant easier to move and position inside your home.

The long leaves also make for great display and décor. They likewise lend themselves well to hanging baskets.

That said, the length of the plant and the number of leaves means that it will need some pruning every now and then.

You’ll primarily be trimming the plant to control its size and shape.

The other important thing to be aware of are its flowers.

Once the flowers have faded be careful not to prune stems with spurs on them. The spurs are where the flowers grow from.

And they tend to emerge from old spurs.

Therefore, you want to keep all the spurs intact so that they can produce blossoms year after year.

If you do cut them off, you’ll lose that potential. And instead have to wait for new spurs to grow  before any flowers will grow from these.

This means missing at least one growing season of blooms.


How to Propagate Hoya Merrillii

Stem propagation is the easiest way to reproduce your Hoya Merrillii. To do so, all you need to do is get stem cuttings.

Additionally, this allows you to choose between water propagation or soil propagation to root the cutting.

Thus, you have a few options.

I’ll go through the steps in detail below.

  • The first step to propagating your Hoya Merrillii from stem cuttings is to look for a healthy stem. You want a stem with at least 1-2 nodes and 2-3 leaves.
  • The node is crucial because without it you won’t be able to successfully propagate the plant.

Next, sterilize your cutting tool. You can sue a pair of scissors, pruning shears or a knife. The important thing is to wipe the blade with rubbing alcohol sanitize it first. Also, use a tool with a sharp blade so you get a clean cut.


Hoya Merrillii Water Propagation

  • To make the cut, snip just below the node. This ensures that the nodes are included with the cutting.
  • Now, it is time to make a decision. You can either propagate the cutting in water or in soil. Both methods work very well so this is more about your preference.
  • To propagate the stem cutting in water, place the cutting in a glass container filled with water. Remove the lower leaves that will end up in the liquid. And make sure that the nodes are submerged.
  • You’ll also want to change the water once a week to keep it from getting murky.
  • Place the cutting in bright, indirect light and a humid location.

In about 2-3 weeks you should see new roots develop.

Wait until the roots are at least 2 inches long. Then you can transplant then into potting soil.


Hoya Merrillii Soil Propagtion

To propagate the stem cutting in soil, prepare fresh, well-draining potting soil and a pot.

  • Instead of placing the cutting in water, here you’ll dab the cut end of the stem in rooting hormone.
  • Then, fill the pot with the soil.
  • Plant the cutting into the soil making sure that the nodes are buried under the mix.
  • Water the soil. You will need to water this when it dries. But avoid overwatering.
  • Put the pot with the cutting in bright, indirect light in a humid location.

In about 3-4 weeks the roots would have grown and taken hold of the soil.


How to Repot or Transplant Hoya Merrillii

The Hoya Merrillii does not need to be repot annually. I usually takes 2-3 years before you need to repot it.

Additionally, it enjoys being slightly pot bound. So you can keep it there for a while longer as well.

However, for best growth, don’t let it get overcrowded in its pot. This will cause unnecessary stress that will affect its overall health.

Also, when repotting, make sure to be careful when handing the plant.

Its roots are very delicate. And if you look at them, you can easily tell they are fragile. Thus, don’t treat them like the bigger houseplants when repotting, otherwise they can experience stress or shock.

That said, repotting is fairly straightforward as you only need to get a pot that is one size larger than its current one. Also, replace the soil while you’re there.


Is It Toxic/Poisonous to Humans, Cats & Dogs

The Hoya Merrillii is not toxic. This makes it safe to keep around kids and pets.

However, it is worth noting that then the stems are damaged or cut, they will leak a milky substance. This is somewhat toxic but not to most people.

For some people, this can cause skin irritation and allergies. Therefore, it is worth practicing caution. And wash your hands if you get any f the milky substance on them.


Hoya Merrillii Problems & Troubleshooting


The Hoya Merrillii is not especially prone to pests. However, like other houseplants it can experience them.

The most common pest issues this plant encounters are mealybugs, scale, spider mites and aphids.

While all of these are tiny, they can cause serious damage to your plant if you don’t spot them early and get rid of them.

The reason in that they grow in number very quickly. So, while each individual bug isn’t much of an issue, collectively, they will wreak havoc on your plant.

Therefore, regular inspection is necessary.

And when you spot any, immediately isolate the hoya from your other houseplants, and start treatment with neem oil.



The biggest concern here is root rot. This is caused by excess water in the soil.

More specifically, root rot happens when you overwater the plant, use soil that does not drain well or a pot with no drainage.

One or more of these can eventually lead to root rot.

The problem with root rot is that is happens under the soil. This means it stays hidden until the symptoms reach the leaves and stems.

So by the time you realize there’s overwatering happening, at least some of the roots have been damaged.

The worst part about root rot is that once too much of the root system is affected, the plant cannot be saved or revived. That’s because the rotted roots have stopped functioning.

As a result, the plant cannot get water or moisture from the soil for sustenance.

Leave a Comment

Your email address will not be published. Required fields are marked *