Anthurium blooms are beautiful – and a bit bizarre. First-time growers usually have lots of questions about this plant’s distinctive flowers, beginning with “What on earth is that thing?” and ending with “How can I get it to make more?” The good news is that if you give them the right care, Anthuriums can flower year-round, producing blooms that last for months at a time.
The most important elements for encouraging Anthuriums to flower are light, temperature, and humidity. That’s why many people have trouble getting them to bloom in the winter when there’s less of all three ingredients. Give your Anthurium bright, indirect light, while keeping the temperature above 65 degrees and the humidity above 65 percent. Under those conditions, your Flamingo Flower should bloom again and again.
Low doses of fertilizer at regular intervals can encourage flowering, but be careful – if other conditions are holding the plant back, fertilizer will hurt instead of helping. An Anthurium that’s not blooming could also have spent too much time in the same pot, leading to a cramped root system or a nutrient imbalance. This detailed guide will help you understand your Anthurium and encourage it to bloom.
What’s Up With Those Flowers, Anyway?
There’s no denying that Anthurium blooms are a bit odd-looking. Each one appears to have only a single petal that ends in a tapered point rather than a rounded edge. And instead of the delicate stamens and pistils that you’d see in other flowers, they sport a single blunt spike rising up from the base of the petal.
The key thing to understand about Anthurium blooms is that what appears to be the flower is, in fact, a more elaborate structure called an inflorescence. The “petal” is really a modified leaf called a spathe, which forms to protect the flowers while they develop and helps to attract pollinators once they’re mature. (You might have noticed that the spathes have the same heart or arrowhead shape as the foliage – this is why).
The spadix – that stubby protrusion stretching up from the wide end of the spathe – holds the Anthurium’s actual flowers, which are quite tiny. Each inflorescence holds dozens of these little flowers at once, arranged in tight spirals all along the length of the spadix.
This basic arrangement of spathe and spadix is common to all members of the Araceae plant family, which are collectively known as aroids. A vast number of popular houseplants are in this category, including (to name just a few):
- Peace lilies
- Arrowhead vines
- Chinese evergreens
- Elephant ears
Some aroids are grown primarily for their luscious and extravagant foliage and their ability to tolerate dim lighting. But those that do flower can keep their blooms for a fairly long time, making them very attractive as ornamental plants.
What Do Anthurium Buds Look Like?
A new inflorescence on your Anthurium will be enclosed inside the spathe at first. It will be shaped just like every other emerging leaf on your Anthurium: a slender stem with an elongated cone of leaf tissue wrapped around the end. This will stretch up and out to the periphery of the plant and unfold to reveal the spadix within.
You can easily tell an emerging inflorescence apart from other new leaves because it will be a faint red color that quickly deepens to the same vivid hue as the mature spathes (assuming you have a typical bright red andraeanum – other variants and species have spathes in different colors).
How Long Do Anthurium Blooms Last?
Anthuriums share the ability of other aroids to produce very persistent blooms. The vivid spathes can stick around for 2-3 months after they emerge, creating a long-lasting pop of color in your home.
When their time is up, the blooms fade and wither away, just like less exotic flowers. So it’s not necessarily a sign of poor health when your Anthurium’s blooms begin to lose their luster. The plant might simply be on the tail end of its flowering phase.
Do Anthurium Flowers Grow Back?
Anthuriums are perennials – the same roots and stems can send up new flowers over and over again. And since these plants are at home in the tropics, they don’t have a built-in dormancy cycle each year. Even if the first round of blooms on your Anthurium has faded, it may flower again in a few months.
In optimal conditions, Anthuriums bloom in a steady rhythm of 2-3 months on and 2-3 months off. Some growers can achieve three or four flowering cycles in a single year!
There’s one important exception worth noting: some commercial growers treat their Anthuriums with a hormone called gibberellic acid to induce flowering. This ensures that the plant will have nice flashy blooms while it’s on the shop floor, making it more attractive to browsing customers.
Anthuriums typically won’t flower until they’re several years old, but gibberellic acid can temporarily force them to bloom anyway. If you have a brand-new store-bought plant, it’s possible that it’s too young to flower naturally, and its current crop of blooms is chemically induced. If so, the plant may take another year or two to produce new flowers after these ones fade.
How to Get Anthuriums to Bloom and Re-Bloom
Consistency is the key to achieving repeated flowering in your Anthuriums. These plants like their environmental conditions to remain steady and mild, with minimal seasonal variation. They’re adapted for equatorial rainforests where winter is pretty much nonexistent.
Unless you live in someplace like Hawaii, recreating tropical conditions in your home will take some work. We’ll talk about how you can improve each of the key factors that Anthuriums need to flower.
The best way to encourage your Anthurium to bloom is to make sure it gets lots and lots of light. Lack of sun is the most common reason these plants fail to flower.
Some readers may find that surprising. After all, Anthuriums are hugely popular indoor plants, and in the wild, they grow in the shade of the jungle canopy. Doesn’t that mean they’re low-light plants?
What’s important to understand here is the distinction between direct and indirect light. Anthuriums can not tolerate much sunlight shining directly onto their foliage. It causes them to lose lots of water from their leaves through transpiration, especially if the ambient temperature is quite hot. The result is dehydration and sun scorch.
However, Anthuriums are quite greedy for indirect light – sunbeams that are diffused through a screen of other leaves or reflected off of nearby objects. Throughout a long, sunny day in the tropics, a wild Anthurium will receive lots and lots of bright but filtered light.
Many rooms can’t match this level of illumination. If your Anthurium’s living space is too dim, it won’t flower. You can often tell that your plant isn’t getting enough sun by looking at its foliage; the leaves turn an especially deep and dark shade of green in low light.
How to Improve Lighting For Anthurium Flowering
Moving the plant to a sunnier spot can often bring out its blooms. The best placement is right by an east-facing window, or a south-facing window that’s covered by sheer curtains.
Here in the Northern Hemisphere, the sun spends most of the day to our south. So a room with lots of windows facing this direction will receive more sunlight than any other part of the house. Hanging a set of semi-translucent window blinds will shield your Anthurium from the direct glare of the sun but still allow it to soak up a healthy dose of light. Whatever material you choose, find curtains with a loose weave that diffuses light but doesn’t block it.
Even without curtains, a south-facing room can still work if you have the space to position your Anthurium 4 to 6 feet back from the window. In that spot, the majority of the light reaching it will be reflected rather than direct. A west-facing window is very similar to a southern exposure in this regard – there’s less direct light, but much of it comes during the hottest part of the day, so it more or less balances out.
You can also put your Anthurium directly in front of an east-facing window, with no curtains necessary. The plant will get a good dose of sun in the early hours when the air is cool enough that the leaves can withstand the glare.
Promote Anthurium Flowering With Grow Lamps
If you find that your Anthurium simply can’t get enough natural light to flower, a full-spectrum grow light might do the trick. If you want your plant to flower throughout the year, you should seriously consider this option – it may be the only way to compensate for the reduction in light levels during the fall and winter.
Grow lights don’t have to take up tons of space and guzzle tons of power to be effective. Energy-efficient LED lights like the Sansi 15W LED bulb can give a significant boost to Anthuriums, and because they don’t give off much heat, you can get them fairly close to the plant without burning its leaves. It’s usually best to place it around a foot from your Anthurium, though some experimentation might be necessary to find the ideal spot for your setup.
Start by giving the plant around 6 hours per day under the lamp and increase the duration gradually, giving it time to adjust. If your Anthurium already receives a few hours of direct sun, six hours of extra energy from the grow light may be enough to get it flowering. In the winter, or in very dim rooms, it may be necessary to give the plant up to 16 hours per day under the LEDs.
Deadheading Anthurium Blooms
Clearing away wilting blooms is a simple way to encourage your Anthurium to produce new ones. As long as those fading flowers remain in place, the plant will see no point in creating fresh ones and will continue to put energy into maintaining that dead weight.
Deadheading the plant will be easiest with a good pair of pruning shears. Some garden gloves will also help because Anthuriums generate sap that may irritate human skin. Snip off the stem of each spent bloom as close to the central stalk as possible. You can also prune away dead and dying leaves; this will also free up some energy for new blooms.
Wipe the blades down with disinfectant between cuts. Otherwise, you could be carrying germs from one part of the plant to the other. Isopropyl alcohol is an effective disinfectant, as is household bleach diluted to 10% strength.
You can also help Anthuriums flower by keeping them at the right temperature. Their ideal range is between 65 and 85 degrees Fahrenheit; they can survive hotter and colder temperatures, but the further below 70 they fall, the less likely they’ll be to produce healthy blooms. Under 60 degrees, you’ll rarely see flowers at all.
Above 90 degrees, your Anthurium might generate blooms, but they’ll often look bleached and faded, and the plant as a whole will likely start to wither from dehydration.
Temperature Tips to Encourage Anthurium Blooms
Even if the average temperature in the room fits the ideal parameters for Anthuriums, your wish for flowers can be foiled by a particularly drafty window or door that’s too close to the plant. Before you set your Flamingo Flower on a sill, check that the window is tightly sealed and that the temperature beside it is fairly consistent.
If necessary, bring the plant to a warmer area during the colder months. If that means moving it away from a sunny window, you can always make up the shortfall with grow lamps.
Some online guides advise putting ice cubes in your Anthurium’s pot to water it. The idea seems to be that the slow trickle of water from the melting ice will keep inexperienced owners from overwatering or underwatering the plant. We don’t recommend this method here at The Healthy Houseplant; the risk of cold shock outweighs the benefits of an easy-to-remember watering routine.
Even if your Anthurium doesn’t show outward signs of damage, mild cold stress from ice cubes could keep it from flowering. More severe cold shock can cause leaves and blooms to turn a dull greenish-brown color, flop over, and die.
Container gardeners may struggle to provide enough moisture in the air to satisfy Anthuriums. Few homes can match the humidity of an Ecuadorian rainforest, especially during the winter months!
Flowering varieties like A. andraeanum can handle dry air a bit better than species like A. crystallinum, which are prized for their huge leaves. Still, if the humidity is consistently below 50%, it may be necessary to give it a bit of a boost to get the plant to flower. You can use a hygrometer to check the moisture level in your Anthurium’s room.
In addition to making it hard for your Anthurium to bloom, low humidity can cause the foliage to develop yellow or brown and crispy patches, especially at the leaf tips. If the plant does produce flowers, they’ll fade more quickly in very dry air.
Boosting Humidity to Enhance Anthurium Flowering
For those with multiple Anthuriums, the simplest way to raise their local humidity is to group them together. Clustering multiple plants beside one another creates a slightly more humid microclimate since they’re all releasing small quantities of water vapor from their leaves. This works better with plants that have similar humidity needs – Anthuriums are best grouped with other aroids.
Another common trick is to give your Anthurium a quick spritz each morning from a spray bottle filled with lukewarm water. Use a fine mist setting so that the droplets will evaporate in a few hours, reducing the risk of fungi breeding on the wet surfaces of the leaves. It can also be helpful to have a fan in the same room for airflow, as long as it’s not pointed directly at your Anthurium.
A more low-maintenance option is to set the plant’s pot on a pebble tray – a flat-bottomed, shallow dish filled with smooth rocks or gravel and a thin layer of water. Evaporation from the dish helps the air stay moist around the leaves, while the pebbles prevent the pot from sitting right in the water where the plant might develop root rot.
There’s one other tool you can use to increase the humidity, and if you feel the same way about dry air as Anthuriums do, you may already have one in your home. That’s right; we’re talking about a humidifier. The better models can switch between warm and cool mist, offering a little bit of temperature control for your plants along with the humidity boost. For more information on humidifiers, click here.
Container-grown Anthuriums might be hesitant to flower because they don’t have the nutrients to spare. Most plants can survive for quite a while on just air, water, and sunlight, but surviving isn’t the same thing as thriving. Your Anthurium needs a few extra elements to build its lovely blooms.
In nature, these nutrients would come from rainwater and the decaying remains of nearby plants. In the home, you’ve got to supply them yourself. If your Anthurium isn’t flowering despite getting enough light, warmth, and moisture, it may have used up all the nutrition in its potting soil.
Other symptoms of nutrient deficiency can include:
- Limited growth
- Deformed leaves
- Dull, dark foliage
- Yellow or dark brown patches between the veins of leaves
Using Fertilizer to Promote Anthurium Flowering
You can make up the shortfall in your Anthurium’s diet with small, frequent doses of liquid fertilizer. This method is great because you can control the dilution and rate of application very precisely, allowing you to test different ratios and schedules and see what works best.
Start by adding one-quarter of the dosage recommended on the package every time you water the plant. A slow and steady stream of nutrients mimics the way Anthuriums get their food in nature.
Please note: fertilizer is only helpful when the plant is actively growing. If your Anthurium isn’t putting out new growth because it’s not getting enough light, for example, it won’t be able to use the extra nutrients you’re providing. Instead, the excess fertilizer can harm the roots by drying them out.
It’s best to wait until spring to try putting your Anthurium on a regimen of fertilizer. Avoid fertilizing in the winter unless you’re sure that the plant has everything else it needs to grow.
Growers who prefer more natural measures might want to use compost instead of chemical fertilizer. Worm compost is usually the best bet; it helps to aerate the soil in addition to adding nutrients. You can mix it in when you repot your Anthurium or spread roughly an inch of it over the top of the potting mix once or twice per year.
Compost releases its nutrients gradually. That means it’s not a good fix for urgent malnutrition issues, but it’s also less likely to give your plant fertilizer burn. This article covers both organic and chemical fertilizers for Anthuriums in more depth.
Soil Flushes to Correct Fertilizer Buildup
As we’ve already noted, too much fertilizer can do your Anthurium more harm than good. What we didn’t mention is that these problems can arise even if you’re watching your plant’s diet as carefully as a bodybuilder’s coach.
Pretty much any amount of liquid fertilizer will leave behind some unused mineral salts in the potting mix. Over time, those little deposits build up to a higher concentration than your Anthurium can handle. The early stages of salt buildup will simply slow down the plant’s growth and suppress flowering, but as the problem gets worse, it can cause dehydration and even death.
You can prevent this issue by washing the minerals out of your Anthurium’s pot every once in a while with a thorough soil flush. Place the container in your shower or sink, or bring it out by your garden hose, and give the plant the most thorough watering of its life.
Lukewarm water works best because you won’t be risking temperature shock. Keep watering until you estimate that enough liquid has passed through the soil to fill up the pot three or four times over. You’ll want to repeat this process once every three or four months. Note – this only works when your Anthurium is properly planted in a container with drainage holes.
Bear in mind that fertilizer isn’t the only way mineral salts can wind up in your Anthurium’s soil. Tap water in many places also contains high concentrations of these chemicals, so giving your plant water from the faucet can also lead to salt accumulation in the long run.
Container Size and Anthurium Blooms
An Anthurium that remains in the same container for long enough will eventually outgrow it. When the root system is packed too densely inside the pot, it will be unable to take up water and nutrition effectively, and the plant’s growth and flowering will come to a standstill. Repotting the plant every so often can help it remain healthy.
This is a little tricky to balance because a pot that’s too large will also slow down flowering; the plant will be so focused on expanding to fill its new space that it won’t devote much energy to creating blooms. Your best bet is to repot once every 2-3 years, increasing the size of the container by roughly 20% each time.
Revitalize a Tired Anthurium by Dividing
Anthuriums can last for quite a long time, but they sometimes begin to bloom less vigorously later in life. Though this aging process is natural, there is a surprising way around it: splitting the plant apart at the roots.
This is a common method of cloning or propagating Anthuriums. In addition to helping you expand your collection, propagating by division can bring back your aging plant’s blooms. Once the new clones recover from the shock of splitting, they’ll start flowering just like a plant in the prime of its life.
The process is surprisingly simple. All you need to do is uproot your Anthurium, grip one half in each hand at the base of the stalks, and tug it apart until the roots separate. Use a firm, steady pressure rather than a sudden tearing motion. Then place each half in a new pot. Until the clones begin sending out new growth, be extra careful to keep them humid and out of direct sun.
We’ve written up a more detailed guide to splitting Anthuriums, available here.
Most of the tricks for getting an Anthurium to bloom and re-bloom are also good for the plant’s overall health. When your Flamingo Flower is comfortable and well-cared-for, it’ll show its appreciation by flowering; when it’s trying to compensate for dim light or cold air, it has no time for luxuries like blooms. With patience and a willingness to experiment, you’ll find the conditions your Anthurium needs to shine.