The Hoya kerrii is better known as the Hoya Heart because its lovely green leaves take the shape of a heart. This has likewise led to many other nicknames for the plant including Sweetheart Hoya, Valentine Hoya and Heart-Shaped Hoya just to name a few.
Compared to other hoyas, this is a much slower growing variety. Nevertheless, over time it will grow into a fairly large, dense clump of a plant reaching between 12 to 14 feet high.
As lovely as its leaves are, many growers also chase after the plant’s sometimes elusive flowers.
Hoya Heart plants can bloom multiple flowers at the same time. These show up in white clusters that are magnificent to look at.
But, they can take time to happen. And, there’s no guarantee that they will in any given year.
Hoya Hearts are native to Southeast Asia. And, they love tropical conditions. As such, it is a good idea to keep them somewhere they can enjoy this.
Because of their appearance, they are likewise popular as off-beat Valentine’s day gifts.
Hoya Kerrii Plant Care
Hoya Kerrii Light
Hoya Kerrii can survive in medium to low light conditions. But, it does best in bright, indirect light from the sun. You want to give it natural lighting as much as possible.
And, if you want it to bloom, the brighter the conditions, the better your chances of this happening. However, keep it away from long hours of direct sunlight.
You also want to avoid hot, very sunny locations or that where it stays under the sun’s rays in the afternoon. Otherwise, you’ll see its leaves burn.
This means that if you live in warmer regions of the country, an east facing window is the best spot for it indoors. You can likewise test the north if you stay in hot climate. But here, you want to choose the brightest spot possible since a norther exposure will have the least amount of light of the 4 directions (if you live in the northern hemisphere which is where the United States and Canada are).
If you live in cooler parts of the country, then keeping it in the west or south are more ideal because it will get more sun there.
That said, you also want to avoid areas that are too dim or are full shade. Lack of light will cause your Hoya Kerrii’s growth to slow down.
Thus, in the winter, if you don’t live in an area which gets full sun all year round, you may need to move the plant to a brighter location.
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Hoya Kerrii Temperature
When it comes to climate, the easiest way to gauge the proper temperature for your Hoya Kerrii is to check whether it is comfortable for people to live in.
If it is, they the plant will be happy as well.
That’s because it is tropical in nature. As such, it likes warm conditions that are very similar to what humans enjoys. Ideally, this falls between 60 and 80 degrees Fahrenheit.
But, the Hoya Heart plant can tolerate hotter conditions if it needs to. That, it has not problems with.
However, it cannot survive in frost or freezing temperatures.
The plant is hardy to USDA zone 11. If you live in USDA Hardiness zone 10 and below and keep the plant outdoors during the warmer months, be sure to take it inside when temperatures drop under 60 degrees.
As a final word on this section, keep the plant away from vents, air conditioning, heaters and other places where it can get much colder or warmer very quickly. It does not like fluctuating temperatures. Nor does it appreciate sudden changes.
Hoya Kerrii Humidity
Your Hoya Kerrii is native to Southeast Asia. There, the climate is both warm and humid, except for a few countries like Japan and Korea where it snows in the winter.
As such, your hoya also enjoys very humid conditions. It grows faster and better with moist air.
Ideally, you want to keep humidity at 40% or higher. But, it is not a necessity.
I live in a drier part of the country, Southern California. And, it doesn’t have a problem with regular room humidity here. I don’t even need to mist it. And, it doesn’t experience any ill effects.
If you’ve ever been to Los Angeles, you know that it doesn’t rain much here. That’s why forest fires can happen during the summertime.
However, I do give my hoyas a shower in the sink once very 7 to 14 days. I don’t have a strict schedule, so sometimes it is 1 week, other times it goes up to 2 weeks.
While the extra moisture is temporary, it does keep them happy.
Alternatively, you can mist your Hoya Kerrii 2 or 3 times a week as well. That works just fine if you want to increase humidity.
If you see any signs of stress from lack of humidity, it is a good idea to place the plant over some stones on a tray or saucer of water. Keep the plant’s pot away from the water. You can also group it with other plants.
Both methods will help increase humidity around the plant.
Watering Hoya Kerrii
Your Hoya Heart likes fairly dry conditions. The simple rule here it is better to underwater the plant that overwater it.
There are two things to keep in mind to make this easier to remember. That is your Hoya Kerrii:
- Is epiphytic. That means its roots don’t like staying in moist soil conditions. This makes is different from many houseplants that like slightly damp soil. Instead, it is more like your orchids and bromeliads in that their roots like the water to quickly dry
- It has fleshy leaves like succulents do. This allows it to store water in its foliage. As such, it is drought tolerant. And, will be able to survive infrequent watering. This is also consistent with the first point as it is design to hold enough water so its roots don’t need to get or search for moisture consistently.
Together, this means that your Hoya Kerrii can survive with being watered once or twice a month. In contrast, you don’t want to overwater it.
The plant is more susceptible to overwatering. And, if left in this condition, can experience root rot.
That said, you never want to allow it to completely dry out for long periods of time either.
I water my Hoya Kerrii once every 7 to 10 days in the summer. And, once every 2 to 3 weeks in the winter. Again, I live in Southern California, where we get sun all year round. And, the weather is fair to a bit warm at times.
But, it doesn’t have the very hot to very cold swings of the northeast or even Chicago. So, make sure to adjust according to where you live.
Similarly, consider the type of pot and soil you use. The more they allow moisture to drain, the sooner you’ll need to water. And, vice versa.
I’ve likewise found the deep watering then completely draining the excess moisture works best when you water. You also want to allow the soil to get slightly dry to the touch before watering again.
Your Hoya Heart plant does best in loose, airy, well-draining soi.
Again, this has to do with it being an epiphyte in its natural habitat. Thus, it likes to get a lot of air. It also gets its sustenance from the air (including moisture). So, it does like and need water.
But, it needs this water to quickly dry to go away. This allows for two things:
- The draining of the water allows the small air pockets to be free. Therefore, oxygen can once again reach the roots.
- Drainage also keeps its roots from sitting in the water for long periods. It hates soggy or wet soil. And, its roots can rot if left with wet feet.
This means you have a few options when it comes to potting soil. All of them being fast-draining. You can use:
- Cactus and succulent mix
- Orchid mix
- Sphagnum moss
Any of these soils will work.
And, if you prefer making your own potting mix. You can mix regular potting soil with perlite and orchid bark. The 2 latter amendments are there to improve drainage.
A final thing to keep in mind here is that the Hoya Heart can either climb or trail depending on where you house it. As such, you an train it to go up a pole. Or allow its long vines to drape down from a hanging basket.
Fertilizing Hoya Kerrii
Hoya Heart are light feeders. They don’t need a lot of fertilizer. As such, your approach to feeding is very similar to that of watering. Less is more.
This way, you can adjust and add as needed. But, it is harder to take back.
In the spring and summer when the plant is actively growing, apply a balanced houseplant fertilizer. Make sure to dilute it to half or quarter strength. Another way you can overfeed your plant besides fertilizing too often is to use a very high concentration.
This is a no-no because plant food leaves salt residue. When that accumulates it will burn your plant’s roots. As such, it is not a good idea to use cheap fertilizers which tend to leave more salt minerals.
If you want to save a few bucks doing so, make sure you flush the soil ever 3 or so months to remove these remnants.
Flowering is a big part of growing hoyas because they produce such beautiful blooms. While small, these come in small bunches with lovely colors.
However, blooming isn’t going to happen naturally. And, depending on the variety of hoya you have, it will take different strategies to help it bloom.
For the Hoya Heart is all about two things:
- Lots of bright light
- Cool nighttime temperature
You want to keep note of the second one as bright light is almost a standard for all hoyas if you want them to flower. As such location affects whether they bloom or not. I have a friend whose hoyas bloomed where she originally lived. But, after moving to another state, none have bloomed. And, it’s been 3 years since.
So, unfortunately, there’s no guarantee with these plants.
Another thing to consider is that you have to wait until the plant matures before it will flower. This means you won’t be seeing any blossoms in year 1. So, patience is important.
Also be careful about pruning. You don’t want to deadhead the flowers. Instead, allow them to fall off and leave the stems in tact. Trimming them will force them to have to regrow before they can bloom again.
The Hoya Heart is a slow to moderate growing plant. As such, you won’t need to do a lot of pruning.
Add to that the fact that they like to climb or trail, means that you don’t have to worry about long vines unless they get too long or messy and out of control. Otherwise, these locations will allow them extend.
So when it comes to pruning, it is all about size and shape control. You also want to remove any dead or damaged parts. It is likewise a good idea to prune leggy stems to promote new growth.
But, don’t be too aggressive as you want to leave many short stalks where the flowers will bloom. Hard pruning is a no-no as it will lessen the chances of flowering. At best make you wait a lot longer before the plant can bloom.
There are a few ways to propagate Hoya Heart. The easiest and most commonly used is stem cutting. That’s because you don’t have to go through the trouble taking the plant out of its container, which it dislikes.
And, there isn’t a lot of complicated things to do. Additionally, it has a good success rate. And, takes nowhere as long as starting from seed.
How to Propagate Hoya Heart from Stem Cuttings
- Start by choosing healthy vines. You want to take a section that has at least 2 leaf nodes. Hoya Heart is able to propagate this way because small roots come out of its stem via the nodes. So, you want to have at least 1 node there. Otherwise, the plant won’t root.
- Use a sterile pair or scissors or pruning shears and cut at least 4 to 6 inches of the stem.
- Place it in water. Make sure to remove the leaves that will be submerged into water. Also, change the water every few days to keep it clean.
- After a few weeks, roots will start to develop.
- Wait until you see the roots get over an inch long. Then, move the cutting into a pot with soil.
- You can use succulent and cactus mix or your own soil recipe. Make sure it is fast draining.
- Water as needed. And, keep the plant in a bright place with no direct sunlight. Warm and humid conditions do best for growth as well.
Hoya Kerrii Transplanting & Repotting
Hoya Hearts don’t need to be repotted often. The earliest I’ve had to repot mine was 3 years. The longest was 5. On average, you likely go around 4+ years or so.
That’s because of 2 things:
- It is a fairly slow grower
- They’re more likely to bloom if kept in a tight container
As such, you only want to repot your Hoya Heart if you notice one of these things happening.
- It is beginning to stress. You’ll see slow growth. More importantly problems start happening. Also, stress makes them more vulnerable to pests and diseases. So, you want to move them before these happen.
- The roots are covering the drainage holes. Once a few roots start showing up or begin to overrun the pot, it is time to get ready to move.
- Soil dries very quickly. While quick drying soil can be because of underwatering, hot weather, fast draining soil and a few other things, abnormally quick drying soil means the roots have outgrown the soil. So, they drink whatever moisture is in there rather quickly. Unfortunately, you can’t keep it like this otherwise the water in the soil may not be enough keep it the plant well hydrated enough.
When transferring pots, the best time to do so is in spring or summer. If you live in a warm climate area, you can likewise do it in the fall.
You also want to choose a pot that is at most 1 size bigger. Nothing more.
And use fresh, well-draining potting soil.
Hoya Heart is non-toxic to humans, dogs, cats and horses. So, you can keep them anywhere indoors or outside where your kids and pets wander and play around.
But, it is worth noting that when pets eat plants, they end up throwing them up later on. I know this happens to my dog when she gets mischievous in the garden. Sometimes its dirty stuff she consumes, other times, it is the stems that get stuck and you see her try to cough or throw it up to get them out a few hours later.
Pests and Diseases
While most aspects of Hoya Heart plant care is low maintenance and easy, pests may not always be the case. Since the plant is susceptible to a few of them, it can be a nightmare if you don’t catch them early.
The best case is you never have to deal with them. And, with proper care, this may happen.
However, when kept indoors, mealybugs, aphids and scale can occur. The first is the most common.
I remember back then when I see them I use the hose to get rid of them immediately. This works. But, if they keep coming back or increase in number, you’ll want to use insecticidal spray or a solution of dishwashing soap and water to remove them.