If you’re looking for a great plant to add to your terrarium plant collection, then heart leaf fern might just be the best fit.
Also known by its scientific name as Hemionitis arifolia or tongue fern, heart leaf fern is an epiphyte that is often grown as a miniature plant in terrariums. The name is derived from the plant’s leathery green leaves that perfectly resemble a heart.
You can use this plant as a centerpiece on your windowsill or in the terrarium for extra attention.
While the heart fern is an attractive plant specimen that you can add to your fern collection, it takes quite some effort to successfully grow it as a houseplant. However, with some background information about the plant, your success is almost guaranteed.
And, in today’s post, we’re going to cover everything you need to about Hemionitis arifolia aka the tongue fern.
Introduction to Heart Leaf Fern
In its native environment, the heart fern is a delicate epiphyte that grows upon other trees. It belongs to a category of non-flowering vascular plants with true roots, tall, thin, stiff, and black stems.
Besides, the plant has complex leathery green leaves that perfectly resemble a heart and reproduces by spores.
The leaves are uniquely textured and can rise to 10-inches tall. But what’s more interesting is the fact that the leaves are dimorphic – which means some are sterile while some are fertile.
The fertile leaves (fronds) are shaped like an arrowhead plant while the sterile fronds are heart-shaped upon a thick stem.
Plant profile in Summary
Common name(s): Heart Leaf Fern or Tongue Fern.
Scientific/Botanical name: Hemionitis arifolia.
USDA Hardiness zones: 10
Mature Height: 7 – 10 inches tall.
Mature Spread: 4 – 6 inches wide.
Growing habit: Upright.
Native Area: South East Asia.
Blooming Time: Doesn’t flower and reproduces from spores during spring.
Growth rate: Medium to fast.
Are Heart Leaf Ferns Toxic?
In general, most ferns are toxic or poisonous to pets, humans, and other animals when ingested. Studies have established that some fern species like bracken fern contain thiaminases enzyme.
This enzyme is responsible for causing thiamin or vitamin B deficiency resulting in blindness and loss of appetite in animals.
While the symptoms of ingesting heart leaf ferns haven’t been properly documented, it’s safe to assume they are as toxic as the rest of the other species. Therefore, you should protect your pets from ingesting this plant by applying Bodhi Dog Bitter Lemon Spray which is effective in discouraging your pets from chewing on the plants.
How to Propagate Heart Leaf Fern
Unlike other plants that you can multiply by cuttings or seeds, heart leaf ferns multiply by spores. This is especially true in their native setting.
Therefore, if you want to propagate them, you have two options:
- Propagate their spores (which is tedious with minimal success rate).
- Propagate by divisions (easy).
My favorite propagation method is the former and if you’re like most people, it should be your method of choice.
Easy wins every time:
Since we’ve all opted for the 2nd method, let’s learn how to propagate heart leaf fern by divisions.
First and foremost, you need to have a large enough mother plant to divide. You can purchase a fully grown healthy plant or grow one yourself.
Next, you need to divide the root ball into equal parts with the direct proportion of the fronds. You can further divide them to get four parts or divisions.
Once done, transplant each division into a 4-inch pot and water accordingly.
Pro tip – It’s best to do the propagation in Spring when the plant is actively growing. Furthermore, ensure to moisten the soil before dividing your plant specimen to avoid damaging the sensitive roots.
Growing and Caring for Heart Leaf Fern
When it comes to growing ferns as houseplants, the choice and composition of your potting mix or soil have to be on point. Failure to do this and you’ll have a myriad of challenges later on. This is because these plants are mostly epiphytes which means they grow best on the bark of trees in nature.
Therefore, the soil should be fertile, well-draining, moist, and rich in humus.
To make the soil that has the above characteristics, you should mix 1-part of sand with 2-parts garden soil, 2-parts humus, some fir bark, aquarium charcoal where possible, and most importantly – a moisture-retaining substrate such as moss.
If this is too complicated or tedious for you, any commercial potting mix for orchids could still do the trick.
Watering your Heart Leaf Ferns
You need to thoroughly water your heart leaf fern after repotting or transplanting to avoid shocking the plant.
Subsequently, you’ll have to wait until there’s a lit dryness on the surface of the soil before watering again. Always keep the plant moist but not wet to prevent root rots. Similarly, you should not allow the plant to go into wilt as this will damage the fronds.
It’s also worth noting that the quality of water is just as important as the watering frequency. Ideally, you should use distilled or rainwater for watering your plants.
If you have to use the tap water, let it sit overnight to dissipate any chemicals present, and then use it the following day.
Temperature and Humidity
Temperature is an important determinant of how fast or slow your plant grows. Higher temperatures will induce rapid growth while lower than recommended temperatures will trigger dormancy.
If you reside in areas with warmer temperatures and high humidity, you can comfortably grow your heart fern outdoors. However, remember to provide some shade to protect the plant from sunburn.
For indoor growers, you can grow in a terrarium or a mini-greenhouse where you can easily control the microclimate.
For the best results, try to keep the temperature between 60 and 85 degrees F.
As for the humidity, the more the better starting from 50% and above. Don’t fret if you can’t match with such conditions because luckily, the heart fern can tolerate a little bit lower humidity without any visible harm.
However, if your home is too dry like most homes, you should try to increase the relative humidity by keeping a gravel-filled drainage tray beneath the fern.
Light Requirement for Heart Leaf Fern
These plants prefer bright but indirect sunlight. Therefore, if you’re growing them outdoors, be sure to provide a bit of shade to screen the sunlight.
For indoor plants, place them on a bright windowsill preferably the north-facing one.
If the conditions are right outside, you can shift the plant outdoors once in a while for extra exposure. This will prevent the weakening of the stems and the plant-looking leggy.
Heart ferns are not heavy feeders. But applying some water-soluble fertilizer sparingly can be beneficial – especially during their active growing phase in Spring and Summer.
For optimum growth, apply half the recommended rate of fertilizer once a month or two. Remember to use a balanced fertilizer for instance 15:15:15.
Pruning and Repotting
After your plant has been growing for a while, there’s a likelihood that there would be some dead fronds here and there. Or the plant growing out of shape.
When that happens, you need to be prepared to prune the old hairy fronds to make the plant tidy.
Besides, you should repot your plant in a bigger pot once overgrown or divide the root ball together the fronds in equal parts and transplant them into smaller 4” pots.
Pests and Diseases Management
Lucky for us, the heart leaf fern plant isn’t susceptible to most pests and diseases. However, depending on how you manage pests at home in other houseplants, the plants may be infested with mealybugs, scales, and aphids.
You can mechanically remove these pests by hand or spray with neem oil to manage the magnitude of the infestation.
Pro tip: Always put on your gardening gloves before attempting to pluck out the bugs from your houseplants.
Common problems with heart leaf ferns
Heart Leaf Fern Leaves Curling
There are several reasons why the leaves of your fern will start to curl of a sudden. The main one is lack of sufficient moisture which causes dehydration and subsequent curling of the leaves.
In other words, this is referred to as wilting. Make sure you’re not under-watering your plant and that the soil remains moist often.
The other common cause for this behavior is pests’ infestation – especially scales attack. Monitor your plants closely and get rid of any bugs present as soon as possible.
Heart Leaf Fern Leaves Turning Yellow
The yellowing of the leaves has two implications. The first one is the natural aging of the plant which is mostly manifested in the older lower leaves.
In the second scenario, the leaves will start turning yellow uniformly and it should worry you.
Unless the plant is behaving naturally, yellowing of the leaves is often a sign of either nutrient deficiency especially Nitrogen, too much direct sunlight exposure, or sub-optimal humidity levels.
To correct this, fertilize your heart leaf ferns as recommended, keep the plant humid, and the right exposure to bright but indirect sunlight.
Heart Fern Leaves Turning Brown
From personal experience, while under watering can cause brown spots or general leaf browning in heart ferns, it’s overwatering that causes such problems.
Your previous actions can point you to the root cause. For instance, have recently watered your plant too much? Or has it been a while since you watered?
These questions will help you narrow it down. If you’ve correctly been observing your correct watering practice but you notice the leaves turning brown, then the issue could be your water quality.
Try to water with rain water or distilled water. If tap water is your only option, let it stay overnight before watering the following day.
While Hemionitis arifolia doesn’t look like a fern at all but rather like a philodendron, it’s in every sense an equal amongst the ferns.
If you’ve been looking for some interesting additions to your plant collection, the heart leaf fern is definitely worth considering. With a bit of knowledge on growing and caring and you’re good to go.
I hope you’ve enjoyed reading this post as much as I enjoyed writing it! Is there anything you think I missed out on? Let me know in the comments down below and I’d surely update.