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Hoya is a genus of 200 to 300 varieties most commonly found in the tropical forests of south and south-east Asia according to the University of Florida.
The Hoya Krohniana species is from the Phillipines. For those who are familiar with Hoya Lacunosa, Krohniana is a close cousin.
Lacunosa and Krohniana are both vines with climbing properties perfect for your hanging baskets.
Both are fairly moderate growers as far as Hoyas are concerned.
Both have upright umbels of small white fuzzy flowers with a sweet fragrance.
The center of the flowers has tiny perfectly star-shaped yellow structures that look like they’ve been molded with wax.
Now, for the differences. If you put the two plants side by side, Hoya Krohniana has perfectly heart-shaped leaves, like spades, whereas Hoya Lacunosa has oval ones.
For Hoya Krohniana care use an airy soil mix containing peat, perlite, and orchid mix (fir bark, charcoal, and perlite), Keep temperatures around 25°C (65°F) at daytime and a few degrees cooler at night. Keep the soil evenly moist but not soggy and water multiple times per week in the growing season in case the soil dries out quickly. Filtered and indirect light is the best in order to grow this Hoya properly.
In fact, it’s the waxy succulent foliage that attracts me to grow Hoya Krohniana. The flowers are a bit bigger than Lacunosa flowers too.
One thing to note about Hoya Krohniana care is that it hails from tropical climes of the Philippines, which means it’s easier growing it in equatorial/tropical zones.
Read on to find some tips and tricks on how to grow Hoya Krohniana and the basics of Hoya Krohniana care for all climates.
HOYA KROHNIANA PLANT CARE
SOIL
The Hoya krohniana plant enjoys being potted in a coarse and well-draining substrate. In its natural habitat, it grows on the surface of a plant or a tree and draws nutrients from the air, rain, water, or from debris accumulating around it.
I would recommend you prepare a potting mix containing peat, perlite, and orchid mix (fir bark, charcoal, and perlite).
This will create a considerably airy substrate that will help grow Hoya krohniana well. Peat holds moisture whereas perlite drains better. The right balance is what we need for proper Hoya krohniana care.
It’s common for epiphytes to like the soil to be slightly acidic to neutral. However, don’t fuss over it as soil acidity changes over time.
As long as you use components like peat, there’s going to be some acidity in the soil. If you make garden compost go ahead and use that as well but make sure it’s sterile. Rainwater is another acidity hack.
WATER
Watering for Hoya krohniana care primarily depends on its location and environment.
The Hoya krohniana hails from warm and wet forests in Asia. This species likes it comparatively moist even with its succulence. But too wet can lead to root rot before you even notice.
The trick to correct watering for Hoya krohniana care lies in the soil mix. As long as your soil mix does not excessively hold water, you can water regularly using the topsoil test, i.e. let the top two inches of the soil dry out completely.
However, if your potting mixture tends to hold a lot of water, as is the case with excessive peaty mixes, your Krohniana plant’s roots may rot out.
During sunny summer days in the growing season, you can follow a higher watering frequency like 2 to 3 times a week.
If you live in the colder zones cut down watering to as low as once in 15 to 21 days and use lukewarm water.
One useful Hoya krohniana care hack is to harvest rainwater when you can and watering with that.
LIGHT
I would describe Hoya krohniana care requirements for lighting as “moderate”. The Hoya krohniana species naturally grows on treetops under their canopies. It is accustomed to receiving diffused and indirect sunlight.
You should grow Hoya krohniana in bright, filtered, and indirect sunlight for healthy growth. If you choose to grow Hoya krohniana inside the house, you can place the plant about 3 feet away from the east window or west window.
Lighting is an essential part of Hoya krohniana care to induce flowering. Hanging your basket to the bough of a tree in your garden can be a good idea for filtered light exposure except that the leaves get a bit dusty.
In winter months, allow the plant at least 10 to 12 hours of exposure everyday if you want to grow Hoya krohniana under LED growlights.
TEMPERATURE
You cannot grow Hoya krohniana in extreme weather conditions, neither hot nor cold. It is not hardy and foliage will burn and die if exposed to frost.
The bottom continual temperatures that it can handle is 10°C (50°F) and the maximum continual temperatures above which it’ll suffer is 25°C (77°F).
Maintain around 25°C (65°F) during the day for ideal Hoya krohniana care conditions. During the night, it enjoys a temperature range between 12°C to 18°C (54°F to 64°F).
If you live in the Northern zones, where your Hoya may be exposed to chill-damage, bring it indoors before frost hits.
Grow Hoya krohniana in a heated room or in a greenhouse to outwinter it, away from direct cold drafts or hot heater/AC gusts.
HUMIDITY
The most important dimension of Hoya krohniana, more than even watering, is humidity requirements. The Hoya krohniana prefers moderate to high humidity, ranging from a minimum of 60% to a maximum of 80%.
The Krohniana cannot tolerate less than the optimal humidity levels for long, so maintaining their desired humidity level is essential. There are several ways by which you can establish the necessary humidity levels.
One way is to make use of a humidifier, which will help maintain the preferred humidity.
Misting and sponging in winters is advisable if you have them indoors. However, don’t keep the leaves soggy wet because that leads to infections.
FERTILIZER
I grow Hoya Krohniana in a soil mix rich in organic manure and don’t believe it needs a lot of fertilization.
A lot of sterile and decomposed matter mixed with rich soil does the trick.
In addition to this, my bi-monthly Hoya Krohniana care schedule includes an organic orchid fertilizer (slightly higher in phosphorus) that you can pick up from your local store.
Try using a liquid one which is easier to administer. This is just to boost the blooms and to be used only in the growing months.
You must stop feeding the plant in winter. The winter Hoya Krohniana care must be limited to just moisture management.
If you avoid chemicals you’ll have to worry less about overfeeding or harmful salt build-up.
PROPAGATION
You can propagate and grow Hoya Krohniana from herbaceous or woody stem cuttings. They take root quite readily and reach a stage of flowering in about two years from cutting.
Professional growers are known to allow pods to dry on the plant, break them open to collect seeds and propagate them through germination.
But the seeds do not store well and need to be sown as soon as possible.
Another reliable way of propagating Hoya Krohniana is through layering. This is indeed my preferred method simply because of its higher chances of success.
GROWTH
I would suggest you grow Hoya Krohniana in at least one hanging basket because they look beautiful grown like a pendant plant.
The heart-shaped leaves are quite small – 1.5-3.5 cm long and 1.5-2.5 cm wide with raised nerves, especially the vein in the middle.
Hoyas are simply vines that grow on trees so they do well even as a climbing vine trained on to a trellis so you needn’t miss out on this plant just because you don’t have a hanging spot.
In fact, you’ll see small aerial roots all along the stem of this plant suggesting that the vines are adventitious.
It is a small to medium size plant and moderately slow growing making it great for indoor growing in pots.
When the vines get long, spiral them back on the trellis so that your plant has a compact and bushy look.
You can prune the plant but take care not to cut off peduncles. Hoya peduncles flower several times year after year.
They live to flower, so deadheading peduncles will drain their energies unnecessarily.
POTTING
Due to their epiphytic nature, you can grow Hoya Krohniana slightly root-bound in a small pot. This also prevents the roots from floating in moisture by naturally limiting the amount it can hold. Therefore, repotting the Krohniana plants often is not necessary.
If the roots look too cramped inside the pot only then do you need to consider repotting.
Using a netted pot with a liner is a great idea for Hoya krohniana care because it enables you to examine the roots.
If you feel your Hoya is overgrown just lift the entire root ball and put it in a bigger pot with more potting mix. In any case, don’t try to untangle the roots, they don’t like it.
STEP-BY-STEP GUIDE TO HOYA KROHNIANA PROPAGATION
One Hoya krohniana care principle that I adhere to is to propagate regularly and abundantly.
I do about 3 to 5 cuttings every growing season from a mature plant. This is my best hedge against losses. Plus, I get to give away Hoyas to one and all and spread the joy!
Propagate Hoya Krohniaha through cuttings
- Wait until June, just ahead of the growing season in the tropics. Use a healthy herbaceous tip cutting from a bug-free mother plant.
- It must have about 3 leaf nodes. Pluck off the leaves from the lower node.
- Let the cutting rest for a day until the cut forms a callous.
- You can use rooting hormone powder but it normally sprouts even without.
- Pop it in a good soil mix with good draining (can’t stress draining enough) in a 4” pot. 50/50 peat and perlite is a simple and effective rooting soil mix.
- Keep the mix moist but not wet and never let it dry out. Keep the cutting in the warm shade until the plant establishes itself.
- Pro-tip: Group the pot along with other plants. This gives the cutting shade and much-needed humidity.
- Don’t disturb the cutting until established.
Propagate Hoya Krohniaha through water rooting
This method is great given the abundant aerial roots on Hoya Krohniana’s vines.
- Take a fresh cutting of a healthy step tip with about 2 nodes and plenty of visible aerial roots.
- Take a tall glass jar that’s 3/4th as tall as the cutting – a jam jar works.
- Fill it up with dechlorinated water or RO water and add a single drop of a good liquid rooting concentrate.
- Place your cuttings in this jar and keep it undisturbed in a place where the temperature is maintained between 65 – 75°F (18 – 25°C)
- It takes anywhere between 2 weeks and a month for the roots sprouting out of the nodes.
- Once the roots are about an inch long and strong, transfer cutting to potting soil.
Propagate Hoya Krohniaha through layering
This method is my fav because it’s non-invasive. Again, you simply take advantage of the aerial rootlets along the stems that develop as you grow Hoya Krohniana.
- Identify a low dangling stem with aerial roots.
- Carefully lower this stem into the soil of the same pot or into another pot making sure the nodes with the rootlets are in the soil.
- Hold it firmly down in the soil with hairpins. Careful not to snap the stem.
- You could apply a bit of rooting hormone powder at the nodes along the stem.
- Continue your Hoya Krohniana care as usual.
- In some time you’ll observe roots sprouting out of the nodes.
- Once established you can simply cut its umbilical connection with the mother plant and let it grow into a separate plant.
- Pro tip: DON’T constantly check for roots. Your chances of success improve if you forget about it for a few weeks.
Seeds can be used as well, but it takes several months for the pods to dry out before they split open and throw out hairy flossy seeds. Only freshly harvested seeds germinate successfully.
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COMMON PROBLEMS FOR HOYA KROHNIANA
The Hoya krohniana naturally grows in harsh forest conditions. It does not fall prey to diseases often, but in case it does, here’s how to get around the issue.
PESTS AND BUGS
The Hoya krohniana is a fairly resistant plant. However, often mealybugs attack its leaves. If infected, begin treatment with sharp water sprays to bring the bugs down the plant. Next, use insecticidal spray or soap and use it thoroughly on the Krohniana plant’s leaves.
Another frequent attacker is Aphids. They can be present on the Hoya krohniana’s flowers or leaves.
For preventing the aphids and mealybugs, use insecticidal spray or soap. You can also mix horticultural oil or neem oil in the spray. These are preventives, no so much curatives.
If you ever see pests on your Hoya, blast them out with a water jet and sponge your plant until clean.
Let the leaves dry out in a well-ventilated spot. Post this you can introduce a routine insecticidal soap spray routine once in two weeks.
Yellowing leaves: a sign of too much water. It’s a good practice for Hoya krohniana care to let the soil dry out between watering. If the soil is staying too moist for too long, consider repotting into a mix as described above.
Thin or wrinkling leaves: Thin papery leaves are a sign of stress in Hoya krohniana. Wrinkled leaves may indicate the plant is thirsty and needs water.
If the plant has wrinkled leaves despite the soil being sufficiently moist it could mean root rot.
Unpot the plant and examine roots are healthy if you see signs of decay then salvage healthy stems for propagation.
Slow or no growth: The typical reasons for this are too little light, soil poor in nutrients or a poor watering schedule and just the typical Hoya moodiness.
If it’s a soil problem adding a balanced orchid meal to the potting mix or any organic fertilizer should help.
However, my first advice would be to be patient! Overdoing any corrective measures can be more damaging than helpful. Make small changes and observe the plant’s response.
Misshapen leaves: This is normally because of stress during the production of the leaf – maybe the plant was over/under-watered, the temperature was too high/low or under/over-fertilized. Once conditions improve the plant will revert to healthy leaves.
Vines dying back: Many Hoya sends out leafless vines to seek out spots of sunlight and branches to twine and climb.
Given time and light, these vines will produce leaves. However sometimes the plant will decide the vine is not viable and it will die back – if you see the tip of the vine shrivel then it is safe to cut it off. Just make sure it isn’t a peduncle.
TIPS FOR GROWING HOYA KROHNIANA
- Water it like a succulent. Less is more.
- Mist your plant with occasionally with rainwater only in the mornings. Foliar feeding of rainwater is what epiphytes get in their natural environment
- A bright spot and a lot of indirect sunlight is the best diet for blooms.
- Don’t prune the flower peduncles. They will bloom again for several years.
- Feed it an orchid fertilizer during growing months.
- Use a small size planter because the roots like it cramped.
- Check regularly under the leaves and nodes for bugs and best to never let it get to a full blown infestation. If you spot a mealybug or two, dab them with alcohol dipped earbuds.
- Wipe the leaves with a wet cloth. It brings out the shine in the leaves and is a good pest control measure.
- Don’t expose it to cold drafts or direct sun.
- Winters, indoors.
FREQUENTLY ASKED QUESTIONS ABOUT HOYA KROHNIANA
WHY IS MY KROHNIANA NOT FLOWERING?
This can be due to various reasons, including frequent unnecessary repotting and provision of insufficient sunlight. Let the plant be slightly root-bound and grow it in a partially sunny spot with dappled sunlight.
WHEN DO HOYAS START FLOWERING?
Most of the Hoya species, including the Krohniana, bloom when mature. Normally, within 2 to 3 years under proper Hoya Krohniana care conditions, you’ll start seeing blooms.
SHOULD I MIST MY HOYA KROHNIANA?
Misting with rainwater is an effective form of foliar feeding recommended in Hoya Krohniana care. Make sure you mist only in the mornings so that leaves have time to dry out, or they become susceptible to infections.
IS HOYA KROHNIANA A SUCCULENT?
The plant has slightly thick leaves, so it has succulent like properties. The care requirements are similar to that of epiphytic succulent Hoyas.
DOES HOYA KROHNIANA GROW AND BLOOM UNDER ARTIFICIAL LIGHT?
They have been observed to bloom under florescent light kept on for about 12 hours a day. If you have low light issues this is your workaround.
ARE HOYA LEAVES TOXIC FOR PETS?
Although Hoya plants are not toxic to cats or dogs, they could still make an animal sick. The digestive systems of cats and dogs are unable to break down the leaf sap of the hoya plant.
CONCLUSION
The Hoya krohniana is available in a few popular variants, one with leaves that only have white flecks and one that is plain green.
It can even have dark, almost black leaves, while some of the leaves stay green as well or a mixture of the two.
The speckled plant goes by the name Hoya krohniana ‘Eskimo’ in nurseries. Whatever the variety, Hoya krohniana care requirements don’t change.
This Hoya is, just like the Lacunosa, very easy to grow and if you pot several cuttings in the same pot you will soon have a nice bushy plant.
Read about the Hoya Linearis next.
Daniel has been a plant enthusiast for over 20 years. He owns hundreds of houseplants and prepares for the chili growing seasons yearly with great anticipation. His favorite plants are plant species in the Araceae family, such as Monstera, Philodendron, and Anthurium. He also loves gardening and is growing hot peppers, tomatoes, and many more vegetables.