The Hoya Sipitangensis is a vining plant that can get long and bushy. It has small green leaves that are probably best known for turning purple-link when sun-stressed.
This puts the plant in the same classification as the Hoya walliniana and Hoya surigaoensis. All three can turn a reddish hue when given bright sunlight.
However, each one produces a different color-hue combination from such an effect.
Therefore, if you like this kind of look, these are some plants to add to your collection.
The Hoya Sipitangensis is native to Southeast Asia, particularly Thailand.
How do you care for the Hoya Sipitangensis? Place the plant in medium to bright indirect light. It needs good lighting to flower.
Additionally, good humidity, leaving it slightly root bound and feeding with high phosphorus fertilizer helps it bloom.
Keep it in a warm spot and allow the soil to partiall between waterings.
Hoya Sipitangensis Plant Care
The Hoya Sipitangensis enjoys medium to bright indirect light indoors and semi-shade outdoors.
The plant grows very well in indirect, filtered or dappled light as it is used to living under the larger trees in the tropical Asian Forests.
As such, the leaves, branches and larger plants do block out the harshest rays of the sun.
Still, the plant gets good amounts of lights through the gaps in between the trees and the leaves.
One unique thing that the Hoya Sipitangensis has as with a few other hoya varieties is that its green leaves will turn reddish pink when sun-stressed.
This is something many growers like because of the beautiful colors.
The areas where more sun hits will become reddish pink while the others remain green. On the other hand some growers will let the entire plant turn its color as well.
This is the “in-between” area where the plant gets a little bit more sunlight that it needs. It can tolerate this and there’s no problem here.
However, avoid going overboard.
If you want to make its leaf color turn reddish-pink, you’ll need to experiment a bit and pull it back when too much sun is there.
That’s because excess direct sunlight, especially from that in the mid-afternoon can burn its leaves. The Hoya Sipitangensis can only tolerate 2 or at most 3 hours of this intensity on a regular basis.
Again, this is due to its position in the forest.
On the other hand, while the plant can tolerate low light as well, I don’t suggest too little light.
This can make the plant leggy in addition to causing it to slow down in growth.
Therefore, if your home does not receive plenty of light, you can use artificial lighting. The Hoya Sipitangensis does very well in fluorescent lights as well as LED grow lights.
So, you can choose what you want to use.
Artificial lights can be used to supplement sunlight or on their own if needed.
The Hoya Sipitangensis likes warm temperatures. Ideally, anything between 60 to 90 degrees Fahrenheit will work well.
For best results, stay in the middle part of that range (68 to 86 degrees Fahrenheit).
This is what makes the plant easy to care for in terms of climate.
It can tolerate a wide range of conditions especially on the warm side.
Again, this is because it comes from Southeast Asia which is very near and around the equator. Therefore, the weather the Hoya Sipitangensis is used to is pretty much sunny and warm to hot.
It can also tolerate rainy season while comes around during late summer through fall.
But that’s just about it.
In that region, there is no snow and there is no cold weather.
This is why the Hoya Sipitangensis has problems with temperatures below 55 degrees Fahrenheit.
As such, the plant likes the outdoors in USDA Hardiness Zones 9 to 11. And it can be kept outside all year long if you wish.
However, if you have four seasons, avoid leaving the plant outdoors during winter as it cannot take the cold during this time.
Ideal humidity for the Hoya Sipitangensis is between 60% and 75%.
Again, this is because in addition to being warm to hot, the Southeast Asia is very humid. In fact, it is consistently humid all year there.
You’ll probably see the lowest humidity during the driest parts of summer where it can drop to 50% or a few points below that. But not much less.
On average, humidity runs between 60% and 75% most of the year.
And during the rainy season, it can easily hit 85% to 92%.
This is why the Hoya Sipitangensis enjoys this kind of moisture in the air. And it will grow at its best in this condition.
That said, it can tolerate 50% humidity and slightly less.
However, I do suggest in going below this level as you won’t see the plant grow optimally. Additionally, it is less likely to flower if humidity is not high enough.
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How Often to Water Hoya Sipitangensis
The Hoya Sipitangensis likes regular watering. That’s because it enjoys moist soil.
On average, this comes out to about once a week watering.
What makes it tricky is the balance. That’s because while the plant enjoys a good amount of water, it cannot tolerate lots of moisture.
This is because it is an epiphyte.
Therefore, in the wild, it does not live in the soil. Instead, it climbs up trees and clings onto them. So, its roots are exposed to the air.
This gives the roots lots of oxygen to soak in.
Similarly, when it rains, the roots dry fairly quickly since they’re exposed to light after and there’s good airflow.
But if you keep the plant in soil, the roots can end up sitting in water for long periods of time if you water too frequently.
Since soil holds moisture, the roots will stay wet more than they want.
Even worse, the water will push out the air leaving the roots drowning and unable to breath oxygen. If this lasts too long, the roots suffocate and die. That’s how you get root rot.
Therefore, if you grow your Hoya Sipitangensis in potting soil, allow part of the soil to dry between waterings.
Ideally wait at least for the top 1-2 inches of soil to dry before watering again.
If you’re not sure, don’t water. The plant will tolerate dry periods better than wet.
Also, always keep an eye on its leaves. Yellow leaves often indicate overwatering while brown leaves mean underwatering.
So, if you see leaf discoloration, it is always wort giving the soil a check to see if it is wet or dry.
The Hoya Sipitangensis needs light, airy soil that is rich and well-draining. The latter is the most important factor given that the plant is susceptible to overwatering.
For this reason, it is important to always make sure that the potting mix you use has components that promote drainage.
This includes perlite, pumice, vermiculite, coco coir, orchid bark and charcoal to name a few. Any of these will work And you can combine a couple as well sometimes to get the best features of each.
Well-draining soil works really well for the Hoya Sipitangensis because it will hold some moisture but quick drain the excess.
This allows the roots to stay hydrated but at the same time keep them from sitting in a lot of water.
The good news is that the perfect soil for the Hoya Sipitangensis is easy to make. And all you need are a few ingredients.
The simplest mixture you can use is:
- 2 parts peat moss
- 1 part perlite
Or you can likewise use:
- 1 part cactus mix
- 1 part perlite
- 1 part orchid mix
In this second potting mix recipe, you can replace the cactus mix with regular potting mix if you don’t have the former.
I also know some gardeners who prefer to just buy their soil from the store instead of making it themselves.
If you prefer to do this, look for African Violet soil. This will work well with the plant.
You can likewise add some perlite later on if you feel the soil needs to drain a bit more.
Fertilizer is an important part of caring for the Hoya Sipitangensis. That’s because it is a long, vining plant that will develop a lot of leaves.
Additionally, you want it to flower.
Its blooms are amazing to look at. Therefore, many growers are more interested in the flowers hoya produce rather than its foliage.
On my part, I like both because the vining leaves tend to complement the flowers.
As such, make sure that that plant gets the nutrients it needs.
That’s the most important thing. In fact, that’s the only thing you need to be concerned with when it comes fertilizing this plant.
This means avoid overdoing the fertilizer or feeding it more than its needs. That’s a no-no.
Another trick I like to do is switch fertilizer products when the right time comes. This helps with blooming.
To do this, feed the Hoya Sipitangensis with a balanced, liquid fertilizer. Only do so during spring and summer. Stop once fall arrives and only start again in spring.
Dilute the application by 50% each time as well by using more water.
To promote flowering, once you see the plant start to bloom, switch to an orchid fertilizer. You can use any phosphorus-based fertilizer.
Phosphorus helps with flowers. And it will encourage the plant to blossom. It also helps make the flowers longer lasting.
Flowers / Blooming
The Hoya Sipitangensis produces beautiful flowers that are white in color and a red to pink center. These are small with each round flower being less than a quarter of an inch in diameter.
However, the flowers grow in an umbel. So, you’ll see bunches of 25 to 30 per umbel.
These flowers typically bloom during the warmer months of the year. And they will last for a week.
They also produce a sweet fragrance.
Their beauty is why it is very important to keep the plant in bright, indirect sunlight. The amount of light is the biggest factor in helping the plant bloom.
To increase the odds of flowering, it is a good idea to keep the plant root bound as well. That’s because it is more likely to bloom when kept in a tight container.
The phosphorus fertilizer also helps.
The Hoya Sipitangensis is a slow grower. But over time, it will grow into a long vining plant.
And if you let it, it will become thick and dense as well.
For this reason, you’ll almost always see it hanging from a basket or climbing up some kind of trellis or shaped wire.
Both allow the plant to get long and full while still looking very lovely.
The plant can get a little bit messy but not a whole lot. So, you may or may not prune it regularly. Some vines can likewise go wayward or become outlies.
Thus, pruning or trimming them off the keep the plant’s shape will work.
Outside of this pruning is usually only done if you want to encourage the plant to keep growing and get thicker. This is a good way to make a sparse plant fuller.
Similarly, remove any dead, yellow, brown or damage leaves as well.
How to Propagate Hoya Sipitangensis
Stem cuttings is the most common way of propagating the Hoya Sipitangensis.
This makes it easy since the plant has lots of stems. Additionally, you can grow several new plants at the same time just by taking more cuttings.
Here’s how to propagate Hoya Sipitangensis from stem cuttings.
- Choose healthy stems with at least 1-2 nodes and 3 or more leaves.
- Sterilize the blade of your cutting tool and snip the stem just below a node. You want to make sure you have nodes with each cutting you take.
- Remove the lower leaves to expose the nodes.
- Then, prepare a pot and fill it with well-draining soil.
- Plant the stem cuttings into the soil with the nodes under the surface. Then water the soil and keep it moist.
In about 2 to 4 weeks new roots will develop and begin taking hold of the soil.
You don’t need to move the plant from the pot until it is time to repot it.
How to Repot or Transplant Hoya Sipitangensis
The Hoya Sipitangensis likes being in a tight pot. And leaving it in this environment increases the possibility of flowering.
Therefore, don’t be in a hurry to repot the plant.
Instead, wait until it needs repotting before you do. For this plant, it is when the roots get quite crowded.
You can also tell as the soil will take less and less time to dry between waterings.
That’s because more and more roots populate the pot which means that they’ll soak up the moisture much faster.
On average, the plant only needs repotting every 2 to 4 years.
When repotting be very careful with overpotting.
Only go up one pot size at a time. And replace the soil each time to repot to ensure that it is not compacted and will continue to provide good drainage and aeration.
Refreshing the soil also lets you replace the depleted nutrients.
Is It Toxic/Poisonous to Humans, Cats & Dogs
No, the plant is not toxic. This makes it a good option if you have young children, cats or dogs who like to play around the house or are very curious.
However, try to discourage them from eating the plant even if it is not poisonous as they can still end up vomiting or choking.
Hoya Sipitangensis Problems & Troubleshooting
The Hoya Sipitangensis can experience thrips, scale and spider mites. While it has some resistance to pests, every houseplant is always at risk of these bugs.
Therefore, if you just got a new Hoya Sipitangensis from the store, always make sure to quarantine it first before putting it alongside your other houseplants.
This will allow you to monitor it for a while for pests, diseases or other potential issues. It also keeps any of these from spreading to your other plants.
After about 2 weeks or so with no problems. You can be sure there are no pests.
Often, pests come from the outdoors or when you first bring the plant home. So, always check and debug.
If you do find any insects, you can use insecticidal soap spray, neem oil or insecticides.
Root rot is very dangerous for the Hoya Sipitangensis as it can eventually kill your plant. Therefore avoid overwatering.
Overwatering not only causes root rot but can lead to bacterial or fungal infections as well. So, be careful with it.
The best way to avoid overwatering is to wait until the top layer of soil has dried before adding more water. Make sure to use well-draining soil as well.
To prevent wet leaves and speed up drying, keep the plant in a well-lit spot with good airflow.