Many new Anthurium owners find that their houseplant doesn’t seem to be very interested in growing, despite looking lush and healthy in the greenhouse or garden store. In temperate climates, it can be tricky to create the conditions these tropical plants need to thrive. Let’s talk about why Anthurium growth can slow or stop, and how you can get it started again.
The most important factors for Anthurium growth are light, humidity, and warmth. Since those factors usually decline in the winter, your plant may appear dormant until spring arrives. It’s also essential to provide the right balance of moisture and nutrition that your Anthurium needs to build new roots, leaves, and stems.
It’s possible that your Anthurium has reached the limits of its container and needs to be repotted. Though some claim that Flamingo Flowers “prefer” to be root bound, they’re actually happiest when they have room to grow. We’ll go into more detail about the ideal environment for Anthuriums, then provide some simple tips for fostering healthy growth in your plant.
How Do Anthuriums Naturally Grow?
Like many popular houseplants, Anthuriums are native to tropical rainforests, where they climb across the trunks and branches of tall trees. Their roots may never touch the ground at all as they’re specially adapted to absorb water from the air or soak up the rainwater that soaks into the mossy leaf litter around them. Decaying scraps of other plants and minerals dissolved in raindrops provide the nutrients the plant can’t get from the air and the sun.
For an Anthurium, the good life looks like a choice perch in the shade of a South American rainforest canopy. There, they can be refreshed by the moist and free-flowing air, moistened by the runoff from intermittent rain showers, and nourished by the dappled sunbeams that filter through the leaves.
A happy Anthurium tends to climb. The main stalk will elongate, often beginning to look pretty woody due to the bark-like stipules that form to shield newly developing leaves. It may tilt and bend toward the direction where the light is strongest, and above-ground aerial roots will emerge from the leafless portion of the stem. These extensions will grab onto nearby objects to support the Anthurium as it elongates.
The roots also put out secondary structures called rhizomes. These are semi-independent sections of the plant that will send up new stems, leaves, and eventually flowers. This is one way that mature Anthuriums can survive and even reproduce if their long vine-like stem is severed.
Over time, a healthy Anthurium can begin to look quite wild, spilling out in all directions in a profusion of entangling roots and big heart-shaped leaves.
In plant stores, you may see Anthuriums growing fairly tall and straight. That’s because they’re reaching toward a single fixed grow light. In their natural habitat, their leaves usually splay out to all sides in order to catch light from different angles.
Why Anthurium Growth Slows Down Indoors
You might have noticed that an Anthurium’s dream habitat sounds very different from the inside of your house. That doesn’t mean that you can’t grow Anthuriums indoors, but it does mean that they won’t be quite as vigorous as they would be in nature – unless you help them along.
Seasonal conditions are the most common culprit if an Anthurium is displaying sluggish growth. The darker, colder, drier days of fall and winter may prevent your plant from putting out new growth. Many growing guides refer to this as dormancy, though it’s different from the true seasonal dormancy of perennial plants from areas with harsh winters. Your Anthurium shouldn’t drop its leaves unless it’s severely cold-shocked.
What if it’s full summer and your Anthurium still isn’t growing? It usually comes down to one of the same factors behind a seasonal slowdown: light, temperature, or humidity. In the wrong spot, the plant might not get enough light even on long summer days. And the interior of your home could be too cold or dry even though it’s hot and muggy outside.
Another possibility is that your Flamingo Flower has been in the same pot for too long. It may have used up all of the nutrients in its potting soil. Or it could have the opposite problem: excess fertilizer built up in the container, stifling the roots.
And, of course, your Anthurium could be getting too big for its britches. When the plant’s root system runs out of room in its pot, it starts to get tangled and cramped, which can also slow down growth.
How Big and Fast Do Anthuriums Grow?
Assuming you avoid all the pitfalls mentioned above, an Anthurium andraeanum – your classic red-blooming Flamingo Flower – should reach a mature height of 12 to 18 inches, with 16 being roughly average. Those figures could look very different for one of the less common varieties. For example, a single leaf on an Anthurium crystallinum can reach five feet in length!
How to Encourage Your Anthurium to Reach Its Maximum Growth Potential
Reaching those maximum sizes will take a while; most Anthuriums don’t grow especially quickly. You’ll usually only need to move yours to a bigger pot every two to three years. Now let’s look at some simple tricks to help your Anthurium reach its full potential.
1: Place Your Anthurium in an East-Facing Window
Anthuriums are sensitive to direct sun, but growers can quickly get over-cautious about sunburn and wind up starving their plants of energy. Your Anthurium needs a fair amount of light to thrive. It just can’t withstand prolonged exposure to direct sunlight – especially during the hottest part of the day.
Is your plant languishing in a dim room? Try moving it onto the sill of a window with eastern exposure. That way, it can soak up a few hours of bright sunlight during the cool early-morning hours, when it’s least vulnerable to sunburn. The added boost of energy will often get your Anthurium growing again.
Another option is a southern or western window with a set of sheer curtains to filter the light. This will protect your Flamingo Flower from scorching, while still giving it the illumination that it craves. Our article on lighting for Anthuriums has more detailed information for those who want to dig deeper.
2: Supplement With a Grow Light
Some homes just don’t receive enough sun to satisfy an Anthurium’s hunger, particularly in the winter. Not many walled-in spaces can match the brightness of tropical sunshine!
Try giving your Anthurium a few extra photons with an LED grow light. These efficient bulbs don’t give off much heat, so they’re unlikely to scorch the leaves. The right distance between the lamp and the plant will vary based on the bulb’s power level; the one linked above can be placed 12-18 inches from your Anthurium.
Depending on how much sun the plant is already getting, you’ll need to keep the lights on it anywhere from 6 to 16 hours per day. We recommend gradually ramping up the amount of light you’re providing; this will help the Anthurium adjust and give you time to spot any stress from the increased illumination.
A simple outlet timer can save you the trouble of remembering to turn the lamp on and off every day. For more suggestions, take a look at our post on grow lights for houseplants.
3: Water Your Anthurium Thoroughly
Dehydration can slow or stop your Anthurium’s growth. When you give the plant water, make sure it gets enough that the drainage holes at the base of the pot are dripping. Otherwise, you can’t be sure that you’ve soaked the soil all the way to the lower roots.
Some houseplant owners like to water every day or two, dispensing the water in smaller doses. We don’t recommend this for Anthuriums. Keeping the soil wet by watering daily can let fungi and bacteria grow out of control, which leads to root rot. You’re better off allowing the pot to dry out somewhat between waterings.
Check your plant’s pot once a week or so to see whether the top layer of the growing medium has dried out; once it has, you can water again.
4: Use the Right Type of Potting Mix
Keeping your Anthurium hydrated isn’t only about how often you water it. It’s also about how much moisture the soil retains. The ideal environment for a Flamingo Flower’s roots is damp but not sopping wet. This mimics the loose, moist organic matter in which these plants grow in the wild.
As canopy-dwelling tree climbers, Anthuriums prefer a potting mix that contains no soil at all. The ideal blend will include spongy material that will stay damp for a while after each watering, along with some coarser ingredients to space out the medium so that excess water can drain away. Experimentation will help you nail down the perfect blend, but a good starting point is an equal mixture of coconut coir, coarse perlite, and chunky pine bark.
The right mix will reduce the risk of both dehydration and root rot, because you can water more frequently without leaving water standing in the pot. You can read more about Anthurium soils and containers here.
5: Check For Drafts
Lack of warmth is almost as bad for your Anthurium’s growth as lack of water or light. Make sure that the plant isn’t in an area where the temperature falls below 65 degrees in the daytime or 55 degrees at night. Windowsills, for example, can be great places for plants – but they can also be quite drafty and cold.
6: Keep Your Anthurium in a Bathroom
When the humidity is lower than 60% in the room where your Anthurium lives, it can become “dormant” even if there’s enough warmth and light. You may be able to enhance your plant’s growth by placing it somewhere with moist air – such as a bathroom with a shower that gets a lot of use.
It’s still important to get all the other growing factors right, of course, and not every bathroom will receive enough sun to support an Anthurium (at least not without a grow light). But your Anthurium will probably feel right at home in, for example, a bathroom with a large south-facing window made of frosted glass.
Brightly-lit kitchens can also be a good choice – although they’re not quite as humid as bathrooms, they generally have more ambient moisture than other rooms in the house.
7: Mist Your Anthurium
Another way to increase humidity around the plant is to mist it from a spray bottle periodically. Use lukewarm water with a fine mist setting – smaller droplets dry more quickly, reducing the chance that fungal infections will take hold in the meantime.
The drier the air is, the more often you’ll need to do this, but most Anthuriums can benefit from a spritz at least once every few days.
8: Use a Humidifier
A humidifier is an even better fix for dry air. These machines are both lower-effort and more effective than misting by hand, though obviously, they cost more. The higher-end models can produce a warm mist that also helps with low temperatures, giving a better simulation of the jungle environment for which your plant is adapted.
Less expensive options are limited to cool mist, but will still do a great job keeping your Anthurium’s leaves moist.
9: Apply Frequent, Weak Doses of Fertilizer
Sunlight, carbon dioxide, and water are the basic requirements for Anthuriums to survive. But to produce new leaves and flowers, they also need a number of organic and mineral nutrients. When you buy a plant at the store, these ingredients are usually mixed into the potting soil. Eventually, the plant will use up its existing supply, which is one reason that growth can taper off over time.
A bit of weak liquid fertilizer may get your Anthurium growing again. Choose a plant food that’s formulated for phalaenopsis orchids, which have similar dietary needs, and dilute it down to about ¼ of the dosage given on the package. Once every 1-2 weeks, add this to the water you’re giving your Anthurium.
This feeding style mimics the slow trickle of nutrition that a wild plant would get from rainwater and rotting leaves. For more information on fertilizing your Anthuriums, check out this article.
A word of caution: adding fertilizer will only help if the plant is already getting enough light, warmth, and moisture. If one of those other factors is missing, fertilizing will harm the roots. Make sure that all other conditions are ripe for growth before you try this method.
10: Flush Your Anthurium’s Pot
As we noted earlier, salt compounds can build up in your Anthurium’s pot over time. This is especially likely when you’re adding fertilizer. High concentrations of these chemicals mess with the root system’s ability to take up moisture and nutrients, preventing it from growing.
If your Anthurium’s growth has slowed down after five or six months in the same pot, try giving it a soil flush to wash out any accumulated salts. You can easily do this with a shower, kitchen faucet, or garden hose. Just run lukewarm water through the container, letting it drain out the bottom. Keep going until about four times the pot’s volume has flowed through the soil.
11: Give Your Anthurium Rainwater or Distilled Water
Aside from fertilizer, tap water is the other primary source of salts in houseplant soil. The drinking water in many cities contains high concentrations of minerals, particularly calcium and magnesium; if you water your Anthurium from the tap, you may be adding those elements to the potting mix.
You can avoid this issue by watering your plant with purified water or collecting rain and using that. Rainwater also gives your Anthurium a bit of nutrition, reducing the need for fertilizer. Find more information on the benefits of rainwater here.
12: Move the Plant to a Larger Pot
If none of the issues described above explain your Anthurium’s lack of growth, the plant may have simply run out of room.
You might have heard the claim that Anthuriums do better when root bound (i.e., when their roots have begun to double back on themselves because there’s no more space in the pot). This claim usually refers to flowering, not growth.
The stress of being root bound may push your Anthurium to bloom because the plant thinks it’s in danger, and it wants to pass on its genes before it dies. As you can probably guess, the terror of imminent death isn’t good for the plant’s health in the long run. It certainly won’t help it grow larger.
When you think your Anthurium has reached the limits of its container, you should switch it to a new pot that’s roughly 20-30% bigger. Check the roots while you’re moving it, and gently spread them out a bit if they’re tightly packed together. Check out our detailed guide on repotting Anthuriums for more info.
Final Thoughts
Now that you know what an Anthurium needs to produce healthy growth, you’ll be much better equipped to diagnose and correct any problems.
Remember that sudden shifts in the plant’s environment can stress it out. Most of the tips above – increasing the light levels, for instance – work best if you implement them little by little.
Above all, watch carefully for your plant’s reaction to your experimental treatments. As you get to know your Anthurium better, you’ll be better able to keep it healthy and strong.