Philodendron is a large genus that includes a wide range of varieties of houseplant species. Known for their vining nature and large glossy heart-shaped green leaves, the perennial plant is often called the “sweetheart plant”.
In addition to their beautiful foliage, these plants are fairly popular due to their easy growth habits. However, there are some reasons why you might find your Philodendron not growing.
There are several factors that can negatively impact Philodendrons’ growth, such as giving them too much or too little water, pest infections, excessive light, high humidity, and more.
If you want to find out more about all the reasons why Philodendron’s growth is stunted and what to do about them, keep on reading this guide!
How Big Do Philodendrons Grow?
Before diving into the juicy details of why your Philodendron isn’t growing as it should, you should first make sure that your plant isn’t actually reaching its natural limit of growth.
One thing that you need to know here is that, as previously established, Philodendrons is a huge genus that has anywhere around 450 recorded species.
Each one of these species will have its average maximum height, which can be as little as 1 ft tall and all the way up to 20 ft. Yet, the most common height is between 3 to 5 ft.
Width is also another factor that varies. Some species can be long and slender while others can be short but very wide, so you have to keep all that in mind.
With that being said, most houseplant varieties will average between 1 to 6 ft wide. Ideally, you should expect your Philodendron to grow around 4 inches every week throughout the growing season.
Factors That Stunts the Philodendron Growth
Philodendrons can be quite a fast grower. However, there are several factors that play a significant role in controlling the growth of your plant.
Unfortunately, if any of these conditions are compromised, the plant’s growth will stop, so let’s have a quick look at the causes behind the Philodendrons’ lack of growth:
1 – Poor Soil Quality and pH
One of the main reasons why Philodendron plants may not grow as fast as they should is that they are planted in poor soil that isn’t helping them grow.
When it comes to Philodendrons, the plant needs fairly rich soil with plenty of essential nutrients and organic matter.
The soil needs to be loose and well drained so that it doesn’t retain water or salts. The ideal pH of the soil should also be anywhere between 5.0 to 6.0, which is considered quite acidic.
This means that if you plant the Philodendron in neutral or slightly alkaline soil, the growth of the plant may slow down or get stunted very early.
Keep in mind that each specific species of the plant will have its own ideal pH range, which can be slightly higher or lower than the average pH of the genus.
If your soil accumulates salt, the plant will also slow down its growth because it is sensitive to salt build-up, which is characterized by stunted growth accompanied by browning of the leaves.
Flushing the excessive salts with water may work temporarily but it’s not a reliable solution in the long run. Instead, you want to replace the soil with a more airy one with better drainage.
2 – Too Much or Too Little Fertilization
Minerals and nutrients in the soil are essential for the growth of Philodendrons. The plant typically needs elements like sulfur, magnesium, calcium, copper, zinc, and iron.
When the plant doesn’t get the necessary micronutrients for its growth, it will stop growing larger.
If you want to improve the growth speed of your beloved Philodendron, you might consider using fertilizers that provide the plant with these elements while having enough drainage to avoid salt build-up.
An ideal type of fertilizer here would be an all-purpose fertilizer with a balanced nitrogen, phosphorus, and potassium ratio (NPK 20:20:20) as well as essential elements for growth.
Despite its importance, you should avoid overfertilizing the plant, which leads to negative results.
For optimal growth, you should fertilize the plant once per month during the growing season from March to August and every couple of months in fall and winter.
3 – Improper Lighting Conditions
Philodendron is originally native to tropical forests of Central and South America. Like many species that belong to this region, the plant requires partial sunlight in order to grow properly.
This matches its original habitat where the plant receives partial shade from larger forest plants surrounding it.
In fact, if the plant gets direct sunlight the leaves will all turn yellow within a few days, all at the same time. Harsh sunlight may even scorch the leaves.
Despite that, depriving the plant of sunlight completely isn’t ideal for them, as too little light can actually cause the leaves to grow apart from each other, which means the plant looks like it’s not growing.
To provide them with the best lighting possible, you might want to put them next to a bright window but still a few inches away.
This way, the plant will still get plenty of indirect sunlight while making sure that the sun rays don’t hit the foliage. You can even use the help of white lace curtains if the UV index in your region is high.
4 – Underwatering and Overwatering
Hydration is one of the most important aspects to consider while taking care of any plant, especially when it is a water sensitive one like Philodendrons.
The challenging part about watering these plants is that they’re prone to both overwatering and underwatering.
For example, if the plant doesn’t get enough water, the roots will start to dry out, putting the plant in a “hazard mode”, which slows down the growth by limiting the supply of nutrients to the healthiest parts of the plant.
You can tell that the plant is underwatered if the leaves are shriveled, yellowish, and break off easily.
Similarly, if you water the plant too frequently, the soil will become waterlogged, which leads to suffocation and serious complications like root rot.
You can tell that the plant is overwatered if the leaves are plumb, shiny, and droopy while the soil is soggy.
These aspects don’t only slow down the growth of the plant, but they also cause the leaves to droop and fall off.
The trick here is to keep the plant’s soil moderately moist rather than stick to a specific watering schedule.
In other words, instead of watering the plant once a week, always perform a hydration test by dipping your finger in the soil or by using a soil moisture meter.
If the top inch of the soil has dried out, you should water the plant. If it still has moisture, you need to wait a few more days before watering.
The hydration requirements of the plant vary depending on the species. For example, climbing species are usually more likely to dry when compared to non-climbing ones, so you have to keep that in mind.
5 – Low Humidity
Humidity is another major metric that you always need to keep in check if you want optimal Philodendron growth.
The original habitat of these plant species is known for high humidity, which is usually anywhere between 65% to 80%. (you can measure the room humidity using a hygrometer)
If you live in an area where humidity levels are quite low, the plant’s growth will slow down significantly.
To avoid that, you might want to use a reliable humidifier near the plant or naturally by putting your Philodendron pots next to each other (if you have plenty).
6 – Inadequate Temperature Control
Temperature is also a factor that can impact the growth rate of Philodendrons if not kept within a healthy range.
As a tropical plant, Philodendrons will typically thrive in a temperature that ranges between 65 to 78 °F (18.3 to 26.7 °C).
If you keep it at a temperature that is much lower than this range, the plant will typically slow down its growth.
To avoid that, make sure that the plant is kept away from the cold drafts of open windows or air conditioners.
You should also make sure that the temperature in the room never falls below 55 °F (12.7 °C).
7 – Continuous Repotting Stress
Since Philodendrons grow too large quickly, you might end up repotting them more often.
Like most other plants, Philodendrons are prone to repotting stress, in which a plant would stop growing for a while and even drop some of its leaves for a period of time.
To avoid putting your plant under too much stress, consider getting a relatively large pot for the plant from the get-go so that you don’t have to repot them frequently.
8 – Diseases and Pest Infections
While plant diseases are rarely an issue when it comes to Philodendrons, they can be a real pain if your plant is infected.
In addition to showing a variety of diagnostic symptoms for each plant, Philodendrons will typically display signs of stress that are similar to repotting stress when the plant suffers pest problems.
This includes stunted growth and leaves falling or changing color. Among the most popular pests that can infect Philodendrons are:
- Aphids
- Spider mites
- Mealybugs
- Various fungi and bacteria
There are plenty of insecticides and chemicals that are used to kill and prevent these pests from attacking your plant. You can also use natural alternatives like neem oil to keep them at bay.
9 – Seasonal Limitations
Another aspect that a lot of growers overlook while planting Philodendrons is the time of the year when they do so.
For example, if you plant your Philodendron in the winter or fall and notice that it didn’t grow much since that time, it is actually pretty natural and you shouldn’t be worried.
This is because these perennial plants are usually dormant during the winter and do most of their growth during the spring and summer.
Some growers might even ramp up the fertilization and water frequency when that happens, thinking that the plant needs more to kickstart its growth, but you should actually do the opposite.
Reduce your watering and fertilization frequency to allow the plant to stay dormant during slow growth months, and the plant should grow up as expected during the warmer months.
10 – Genetic Limitations
Last but not least, as previously established, the plant has a huge variety of species that have unique characteristics.
While some Philodendrons may grow to around 10 to 12 ft high, such as the Philodendron Jose Buono, most of them are only limited to around 3 to 5 ft, including the Billietiae, the Bipinnatifidum, and the Hope Selloum
This also applies to the width. For example, the Xanadu Philodendron is one of the Philodendron species that are wider than they are tall.
For that reason, if your plant is already within this dimension range, there might be a chance that this is as far as the plant goes.
Final Thoughts
This marks the end of today’s guide that walks you through all the reasons why your Philodendrons are not growing.
As you can see, Philodendrons are among the easiest houseplants to take care of, so there shouldn’t be any growth problems as long as you provide them with proper light, water, and climate.
However, if your plant still has room for extra growth, consider following the previously mentioned tips in order to speed up the plant’s growth!
Growing up with a mom who filled her home (inside and out) with all sorts of plants, Lisa got her start in gardening at a young age. Living now on her own with a home and yard full of plants (including an indoor greenhouse), she shares all the gardening tips she’s gained over the years.