The Hoya Krohniana is a rare, uncommon wax plant that has lovely small, heart-shaped leaves featugin silver markings. It is likewise known for growing long vining stems which make it beautiful to look at in hanging baskets.
That said, it does have a few varieties available so you may hear its name mixed with the following subscpecies.
- Hoya krohniana Eskimo (or Super Eskimo)
- Hoya krohniana Silver (or Super Silver)
- Hoya krohniana Black Leaves
The Hoya Krohniana is a epiphyte that has thick leaves that hold water. Thus, allowing the plant to tolerate lower humidity and dry periods.
However, while it does have succulent-like leaves, the plant is not a succulent. Therefore, although you can water it like a succulent, the other parts of its care are different from succulents.
Hoya Krohniana vs. Hoya Lacunosa: What’s the Difference?
One of the things that often come up with the Hoya Krohniana is its comparison to the Hoya Lacuna.
Apparently, there’s sometimes confusion between the two because they look similar in terms of how they grow. This is thanks to their long stem and small leaves.
However, if you place the two plants near one another, you can easily notice that their foliage are different.
The Hoya Krohniana has heart-shaped leaves while the Hoya Lacunosa has oval shaped foliage. Additionally, if you touch the leaves, the Hoya Krohniana has more rigid, firm ones compared to the softer, more pliable ones of the Lacunosa’s.
Similarly, their blooms differ as well with the Hoya Krohniana having larger flowers.
That said, the two plants are close relatives. And they both look amazing in hanging baskets.
Hoya Krohniana Plant Care
The Hoya Krohniana needs light. This makes a well-lit room the best place to put the plant indoors.
It is happiest with medium to bright indirect light. However, keep it away from very strong light or direct sun.
It can tolerate 1-2 hours of direct light on a daily basis, especially if this is from morning sun. But any longer than that, you’re putting the plant’s leaves at risk.
That said, it is important to give the plant enough light because it needs this in order to bloom. Low light or lack of light is a sure way to reducing the chances it your plant flowering.
Try to give the Hoya Krohniana at least 5-6 hours of light daily.
If you don’t have good access to natural light from the sun, you can likewise use artificial lighting. The plant does well under grow lights. But make sure that you keep it at least a few inches from the bulbs as these can burn its leaves as well.
The biggest difference between natural light and grow lights is the amount of exposure the plant needs. Because artificial light does not cover as wide a color spectrum as the sun, the plant will need at least 10-12 hours of artificial lighting daily.
The Hoya Krohniana originates from the Philippines which is located in Southeast Asia. Like many countries in that region, it is very close to the equator.
Thus, it has tropical weather that ranges from warm to very hot.
The coldest times of the year there are between December and February. Although, during this time there is no snow, and the weather only goes down to about 60 degrees or so.
As such, the Hoya Krohniana thrives when temperature is kept between 60 and 80 degrees Fahrenheit. And it will struggle when the climate drops to under 50-55 degrees.
This means you want to keep it away from the cold including air conditioners and drafty places like near an open window.
Outdoors, the plant is well-suited for USDA Hardiness Zones 10 through 12. In these locales, it can grow happily outside 365 days a year. However, below these zones, it is important to bring the plant indoors somewhere more cozy once the weather drops under 55 degrees.
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Another aspect of Philippine weather is its humidity. This ranges from moderate to high depending on the time of year and whether or not it rains.
At its lowers, humidity is about 55% and it will shoot up to 85% or higher on a rainy day. For the most part, expect humidity to stay between 60% and 75%.
As such, the Hoya Krohniana enjoys humidity of 60% and higher. Although it can tolerate slightly lower levels because of its thick leaves which do store water.
This makes them similar to succulents, but different from them. Thus, don’t care for your Hoya Krohniana the same way as succulents.
Ideally try to keep humidity at 40% to 50% to avoid dry, crispy or brown leaf tips and edges. This is a sign that humidity is too low for its liking.
As such, if you live in the desert or somewhere that has very dry air, it is a good idea to mist the plant regularly, Ideally, you can invest in a humidifier as well.
If you don’t want to keep misting, other humidity boosting options include placing the pot on a pebble tray or grouping it along with other plants.
How Often to Water Hoya Krohniana
Due to its thick leaves, the plant can tolerate some dry ness. This gives you quite a bit of leeway in case you forget to water.
In fact, the best way to water your Hoya Krohniana is to allow the soil to dry completely before adding more water. Once the leaves looked a bit wrinkled, then it is time to water.
Then water thoroughly until the liquid starts coming out from the bottom of the pot. This ensures that the roots get enough moisture as the soil is saturated.
After that, allow the soil to completely drain so there’s no water left pooling in the container. This will prevent the roots from swimming in the water which they don’t like doing.
If there’s any water that pools in the saucer under the pot, make sure to throw it away. Otherwise, the soil will eventually absorb that back up.
It is very important to avoid overwatering your Hoya Krohniana as it won’t tolerate much of this. And it will give you signs that it having problems with this like dropping its leaves.
Because weather plays a huge role in how often you water, make sure to adjust your routine based on the time of year.
During the warmer months, you’ll be watering it about once every 7 days or so. In winter this frequency will drop to once every 2 to 3 weeks.
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Hoya Krohniana Potting Soil
The best soil for your Hoya Krohniana is light, airy and well-draining. This ensures that any excess moisture quickly drains to avoid overwatering. Similarly, the loose nature of the soil will allow good air circulation to the roots, which is something the plant likes given that it is an epiphyte.
Additionally, keep soil pH between 6.0 and 7.0 for best results.
As such, the most important thing when choosing soil for your Hoya Krohniana is make sure it includes some kind of drainage. You can use perlite, pumice, vermiculite or orchid bark to achieve this.
Here are some potting mixes that I’ve used successfully with this plant. As always, I try to keep things simple so I’ll limit the components to 2 or 3 per recipe.
- 2 parts peat moss to 1 part perlite
- 1 part potting mix with 1 part orchid mix and 1 part perlite
- 1 part potting soil and 1 part succulent & cactus mix
- 1 part coco coir, 1 part potting soil and 1 part perlite
- 1 part potting soil and 1 part orchid bark
I’ve listed a few so you can go with the ingredients you already have on hand. Also, you can experiment with a few of them to see which one works best based on your home’s environment.
If you don’t like making your own mix, you can likewise pick up African violet mix or a well-draining succulent soil. Both should work well for the plant.
The Hoya Krohniana is a light feeder so avoid overfeeding the plant. That said, it is important to give it plant food as this will allow it to grow faster.
You can use a weak fertilizer or dilute the strength to 50% if you go with a standard houseplant plant food. It is not very picky about what kind you so but more so that you give it nutrients.
As such, one a month application during the spring and summer is ideal. You don’t need to feed it during winter.
Once it starts blooming or is about to flower, switch to an Orchid bloom booster. The difference between this and your standard houseplant fertilizer is that the former has more phosphorus which helps with flowering.
In contrast, the latter has more nitrogen which encourages leaf development and growth.
Use the bloom booster as the plant is flowering then go back to your regular fertilizer after the flowers have faded.
The Hoya Krohniana is known for its long vining stems which contains many small leaves per vine. This makes it amazing to hang or drape, which is why the most popular way to grow the plant is in a hanging pot or basket.
This also lets you leave the vines alone and let them get longer. The longer and fuller the plant gets the prettier it looks.
That said, it is a natural climber which means you can train to go up a trellis or some kind of wires. The plant will send out small aerial roots that will allow it to cling onto these structures.
Because the Hoya Krohniana is a slow to moderate grower, it takes time before it gets longer.
Nevertheless, regular light pruning goes a long way in keeping it looking neat and the shape you want it to look.
The other important thing to keep in mind is not the prune the peduncles after the flowers have faded. That’s because the Hoya Krohniana (and hoyas in general), will grow their blooms form old peduncles.
Thus, cutting these off means they need to regrow again before any flowers can bloom. This will cause you to miss an entire growing season’s worth of blossoms.
How to Propagate Hoya Krohniana
The simplest way to propagate the Hoya Krohniana is through stem cuttings. But you can likewise grow it from seed or propagate through air layering.
But because it has a lot of stems, propagating it this way has become the most common method.
With stem propagation, you can root the cuttings in water, sphagnum or soil. Each of the methods work differently but they attempt to do the same thing, let the cuttings develop roots.
As such, you can choose whichever way you prefer to go.
Here’s how to propagate Hoya Krohniana from stem cuttings.
- The best time to propagate the plant is during early spring to early summer.
- Start by taking a 4-6 inch stem cutting with at least 1-2 nodes and a few leaves on it.
- Remove the lower leaves to expose the nodes.
- Plant the cutting in to well-draining soil (1 part peat with 1 part perlite) that has been moistened. It is important to water the soil regularly during this time to keep it moist. However, avoid overdoing it such that the soil becomes soggy and wet.
- Leave the plant under partial shade in a warm, humid spot.
- Leave it alone and try not to do too much to it as it develops roots.
You can follow the same steps to propagate the cutting in sphagnum moss. The only difference is to replace the potting mix with sphagnum peat moss.
On the other hand, with water propagation:
- Insert the cutting into a glass filled with water.
- Submerged the stem cutting so the nodes are underwater. But keep the leaves above water. If there are leaves that end up in the water, remove them as they will rot after a while.
- Change the water about once a week. The goal is to keep it fresh and clear. This way the plant gets enough oxygen and there are no pathogens that grow.
- In about 3-4 weeks you should see quite a few roots that have developed.
- Once the roots get to at least 1-2 inches long, you can pot them up into soil.
How to Repot or Transplant Hoya Krohniana
The Hoya Krohniana is an epiphyte which means it will take time for it to fill out a pot given that its root system is neither large nor extensive.
Additionally, the plant enjoys being pot bound. And leaving it in such a state (along with giving it lots of light) increases its ability to bloom.
Thus, you’ll see a lot of Hoya Krohniana being underpotted.
This is also why many growers will only repot between 2 to 5 years (sometimes even longer than that).
However, once the plant is very tightly snug in the pot or is getting stressed (and not growing as much) it is time to move it to a larger container.
Choose one that is 1-2 inches wider in diameter. And avoid jumping up more than 1 size as this increases the risk of overwatering and it also reduces the potential to flower due to its looser nature.
Is It Toxic/Poisonous to Humans, Cats & Dogs
No. The Hoya Krohniana is not toxic to dogs, cats or humans. But, you still want to avoid letting pets and young children chew or ingest parts of the plant.
While the leaves and stems are not poisonous or contain any toxic substances, eating them can still cause stomach discomfort and even vomiting just as you would if you ate something that’s not edible.
Problems & Troubleshooting
Why is the Hoya Krohniana Not Flowering?
It takes a while for your Hoya Krohniana to flower because only mature plants bloom. Thus, the plant needs to get past 2 years or so before it can produce any flowers.
Once that time comes, it is important to give it sufficient light to encourage it to flower. Additionally, it stands a better chance of doing so if you keep it root bound.
The Hoya Krohniana can get pests and the most common attackers are mealybugs. That said, spider mites, scale and thrips can come around.
All of these bugs are there to suck on the plant’s sap. As such, you want to spot them as early as possible to prevent them from robbing the plant of its water and nutrients.
This is important because these insects reproduce very quickly. As such, if you let them be, they can quickly turn into a full-blow infestation which is much more difficult to control and eradicate.
The first line of defense is usually jus to stray them off with water.
You can then use neem oil or insecticidal soap to get rid of the remaining ones. Makes sure to get all of them as the adults can lay eggs to start the cycle over again. Similarly, if you leave eggs that are hidden behind leaves, they will hatch and grow into adults that lay more eggs. Again, the cycle continues.
As far as diseases go, you want to watch out for excess moisture. this can cause root rot (which is the most serous one of them all) as well as other bacterial and fungal infections.
By reducing the moisture and letting the soil dry before adding more water you eliminate the risk of having to deal with these pathogens.