The Hoya Rintzii Borneo is also known as the Hoya Rintzii or the Hoya Borneo. It gets its name from where it originated from which is the island of Borneo and areas in the Malaysian peninsula. Both of which are in Southeast Asia just north of the equator.
The Hoya Rintzii is a rare plant. And in a way it is still uncommon because is fairly new as it was only described as a species in 2014.
Like many hoyas, the Rintzii Borneo is an epiphytic climber with long vines that will develop over the years.
It is named after R.E. Rintz, And is related to the Hoya mindorensis and the Hoya erythrostemma.
I’ve had the fortune to come across the Hoya Rintzii during a trip to Southeast Asia.
Oddly enough, I still remember my first reaction upon seeing its leaves. “Something’s not right with that plant”.
Honestly, I thought the leaves had some kind of infection because of the way the speckles looked. There were heavier and bigger than most speckled or splash hoyas. And for this reason, I really believe that the plant’s foliage are an acquired taste.
That said, if you’re into very unique looks, this is something worth going for.
The other thing about its leaves is that they turn reddish color or red-pink when sun-stressed. This is the look I love and the vendor in Malaysia was nice enough to show me some that she grew this way.
She said she intentionally grows them under more sun because that’s the look that’s most popular with consumers.
Another feature are its stunning flowers which grow in umbels. The plant is lovely when you see many umbels at the same time.
Hoya Rintzii Borneo Plant Care
The Hoya Rintzii Borneo likes a bright, indirect light. Its green leaves are lovely but are kind of an acquired taste because they have a certain look.
Therefore, I know some owners who like to sun-stress the plant. By sun stress, they keep the plant under bright sunny exposure.
This causes its green leaves to turn pink or have a reddish blush, making it very unique looking.
Honestly, it looks gorgeous this way which is why many Hoya Rintzii owners will do this.
However, when doing so, you need to find that balance and kind of tow the line.
The reason is, too much strong, intense or direct sun will cause its leaves to eventually burn.
As you would guess, it requires some trial and error. So, if you want to have the plant maintain reddish foliage, start gradually and increase the light slowly.
As a rule of thumb, the plant needs at least 6 hours of natural light daily. If you can’t give it this, try artificial lights, which will work just as well.
The difference is grow lights have limited color spectrum. Therefore, you do need longer exposure compared to sunlight. On a daily basis, this comes out to about 12 to 14 hours a day.
But the same guidelines apply. That is, keep the plant at least 8 inches from the bulbs as these will emit heat which can burn the leaves if too close.
Finally, the reason why sufficient light is important is that the plant needs it in order to bloom. Low light will keep it healthy but reduce its ability to flower.
As you can guess, the Hoya Rintzii Borneo is native to Borneo and the Malaysian Peninsula. This means it lives just north of the equator.
More importantly, it is used to tropical climates.
As such, the Hoya Rintzii enjoys warm, sunny weather the entire year. in fact, it is much better at tolerate the heat rather than the cold.
Because it lives under the shade of the forest canopy, it enjoys moderate to warm weather.
Indoors, the Hoya Rintzii Borneo prefers temperatures between 60 and 86 degrees Fahrenheit. It especially thrives during the summer when the weather is on the higher end of that range above 68 degrees.
This means it can be a little bit more tricky to care for as a houseplant if you live in cooler parts of the country.
Needless to say, keep it away from air conditioned rooms or vents that blow cold air. Also, avoid placing it near open windows where cold drafts or breezes can come in.
Outdoors, the plant is best suited for USDA Hardiness Zones 10 and 11 as these locations have warm sunny weather all through the wear including winter.
You’ll find these locales in the southern coast of the country like the Florida, Louisiana, Texas and the southern part of California.
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One of the reasons why countries near the equator (like Borneo and Malaysia) get very hot is because in addition to the high temperature, they are very humid.
Humidity works both ways in that it makes cold weather cooler and warm weather hotter. For this reason, summers in Southeast Asia (where Borneo and Malaysia are located) are hot and sweaty.
Not only is temperature in the 90s or higher, humidity usually stays between 55% to 75%. Thus, giving you heat index of 100 degrees and more on a regular basis.
As a result, the Hoya Rintzii Borneo thrives in 60% to 80% humidity. This is where it will grow the fastest and produce more foliage.
Unfortunately, unless where you live has a tropical climate, you own a greenhouse, grow cabinet or keep the plant in a terrarium, it is not easy to maintain this range.
The good news is that the plant has thick, semi-succulent leaves.
These store water allowing the Hoya Rintzii Borneo to tolerate dry periods and lower humidity. Nevertheless, there’s still a limit to how low it can tolerate before its leaves get dry and crispy tips.
So, try to maintain humidity of 40% and above indoors.
This won’t be difficult in some places but if you live in a dry area or have hot summers and cold winters, the air can get really dry.
The best way to measure humidity is to get a digital hygrometer is place it in different rooms in you home. This will give you an idea of what humidity is in each location.
If humidity is too low, you can regularly mist the plant, place it on a pebble tray or get a humidifier.
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How Often to Water Hoya Rintzii Borneo
The Hoya Rintzii Borneo does not need to be watered often.
In general, it needs once a week watering during summer and once every 2 to 3 weeks in the witner.
Note that I cannot give you exact numbers here because the temperature and humidity in your locale will influence how much water the plant ultimately needs.
Additionally, the more light the plant gets the faster the soil will dry. Therefore, you need to water more often.
Meanwhile, the higher the humidity, the less you need to water.
These, and a few other factors all come into play in determining the exact number of days which is why you don’t want to use a fixed watering schedule throughout the year.
Spring and summers will need more water because there’s more sun, the days are longer and the climate is hotter. The opposite is true for winter.
The important thing with water is to avoid overwatering.
One reason is that the Hoya Rintzii Borneo is an epiphyte. Therefore, its roots don’t like staying wet. Instead, they enjoys being able to breath and getting enough oxygen.
Secondly, the plant’s thick leaves holds moisture which means it does not need a lot of extra water either.
Therefore, the best way to tell how often to water your plant is to feel the soil. Stick your finger into the soil down to the second knuckle. This comes out to about 2 inches from the surface of the soil.
If the soil at that depth is completely dry, it is time to water. But not before then.
Hoya Rintzii Borneo Potting Soil
The best soil for Hoya Rintzii Borneo is loose, airy and well-draining soil. Again, this stems from the plant’s preferences which I discussed above.
A loose, well-aerated soil will let the roots breathe easily. Its fast draining nature will also allow excess moisture to drain quickly, which keep the roots from sitting in water for prolonged periods of time.
Together, the prevent overwatering and root rot.
You also want to avoid soil that gets compacted as this will prevent air circulation.
Finally, the Hoya Rintzii Borneo thrives in soil pH between 6.0 and 7.5.
So what kind of soil can you use?
Here are some DIY potting mix recipes for Hoya Rintzii that will keep it healthy and happy.
- 1/3 potting soil with 1/3 orchid mix and 1/3 perlite
- 1/3 potting soil with 1/3 coconut coir and 1/3 pumice or perlite
- 1/2 potting mix and 1/2 orchid bark
- 2/3 peat moss and 1/3 perlite or pumice
Does the Hoya Rintzii Borneo Climb?
As the Hoya Rintzii grows, it will develop long vining stems and try to climb. In fact, it will climb on anything it will find given the chance.
To take advantage of its wrapping-climbing nature, you can give it a decorative trellis or a shaped wire. The plant will cover that and take its shape.
Of course, you can likewise allow it to trail. The plant is gorgeous when allowed to grow this way. Thus, many owners will display it in a hanging basket.
The Hoya Rintzii Borneo needs little fertilizer. But it does need it.
Therefore, it is a good idea to feed the plant. Without fertilizer, the plant can still stay healthy although it will grow slower and won’t produce as many or big leaves as it would with plant food.
That said, avoid over fertilizing the plant.
Instead, just follow the instructions on the produce label.
You can use a regular houseplant fertilizer diluted to half strength. Once a month application during the spring and summer will keep it healthy. Stop by early or mid-fall and don’t feed during wtiner.
Flowers / Blooms
The Hoya Rintzii features stunning flowers. These can come in different colors depending on the variety you ultimately get.
The most common bloom colors are white/cream with a red center.
The flowers have star-shape. Although the stars look more like asterisks or Christmas stars where the pointed ends are the wider.
In the center, you have a more traditional looking star with a reddish-yellow middle.
The flowers will appear in a cluster which makes them all the most stunning to look at.
Some varieties will have a more yellow hue to them with most of the flower being yellow and the middle being red. Meanwhile, you’ll likewise see white flowers and yellow centers in other varieties.
This is what makes them stunning.
That said, the flowers and clusters are not big. Although it can produce many umbels at a time which makes it beautiful.
The most important thing about these flower is not to deadhead them after they’ve faded and dropped.
That’s because they grow on perennial peduncles (or stalks). This means the plant will flower again from the same peduncles.
Thus, if you cut them off, you’ll lose the blooming potential.
You’ll also need to wait for new peduncles to grow before you’ll see the plant flower again.
In the previous section, I’ve touched on the importance of not pruning peduncles as the Hoya Rintzii Borneo grows on old growth.
Besides this, there’s not a lot to do when it comes to pruning this plant.
It is quite low maintenance in this regard as it does not grow overly big and has a relatively slow growth rate.
If you keep in in a hanging basket or allow it to climb, you’ll need to trim it even less as you want the vines to grow longer to cover the trellis or drape from the basket.
As such, some light trimming here and there is all the plant needs.
How to Propagate Hoya Rintzii Borneo
Stem propagation is the most effective way to grow more Hoya Rintzii at home. This is a simple method that produces high success rates. It is also the fastest way to grow a new plant (outside of separating it).
The most important thing when propagating via stem cuttings is to take a healthy stem with at least 3 leaves or more.
Try to get one that is 4 to 6 inches long. You can likewise get a longer stem and cut it into segments. Make sure each segment has at least 1-2 leaf nodes to make them viable for propagation.
You can then propagate the cutting in water or directly into soil
The difference between the two methods is that propagating in water allows you to see the roots as they grow (if you use a glass container). You can’t do the same in soil.
But later on, you’ll eventually need to pot up the cutting in soil. You can keep the cutting in water for a long time though. I’ve seen friends keep their cuttings in water for 6 months to as long as 1.5 years.
However, after a year, some roots will start rotting so you do need to keep pruning these off.
How to Repot or Transplant Hoya Rintzii Borneo
Repot the Hoya Rintzii once every two years. It does not need regular repotting as its epiphytic roots are neither large nor are they extensive.
Additionally, the plant enjoys being underpotted which actually encourages it to flower. Thus, it is a good idea to keep it in a slightly tight container.
When the time comes to repot the plant, here are a few reminders.
The best time to repot is spring or early summer
- Avoid repotting when it is very hot or very cold as this adds stress
- Choose a container that is 1-2 inches wider than the current pot
- Make sure the new pot has drainage holes
- Replace the soil with fresh well-draining potting mix
- Check the roots for any rotting or damage. Prune those off if you find them
Is It Toxic/Poisonous to Humans, Cats & Dogs
The Hoya Rintzii Borneo is not toxic to cats, dogs and humans. Nevertheless, it is not a good idea to allow pets or young children to chew or ingest parts of the plant as this will cause side effects, albeit non-poisonous.
Problems & Troubleshooting
The Hoya Rintzii Borneo can be prone to pests. However, the healthier it is, the better its resistance to these bugs.
Similarly, because pests are attracted to dust, it is a good idea to wipe the dust off the plant’s leaves every now and then.
The most common pests that will come around are the sap suckers. This includes mealybugs, spider mites and aphids.
If there’s a lot of moisture around, it will attract fungus gnats as well.
Speaking of excess moisture, that’s the one thing to avoid if you don’t want your Hoya Rintzii getting any infection or diseases.
Both leaf and root diseases are usually caused by excess moisture.
With leaves, getting them wet without letting them dry quickly enough can result in leaf spot, blight and mold infections.
With roots, root rot can happen if the soil is overwatered or retains too much moisture.