The Philodendron radiatum plant is all the rage among plant owners. Its large, uniquely shaped leaves make it a very attractive decorative houseplant.

Philodendron Radiatum Care Infographic

We have brought you the most comprehensive plant care guide containing secrets from seasoned experts. Find out these little-known secrets by reading ahead.

What Is a Philodendron Radiatum?

Philodendron radium’s common name is the split leaf plant. It has large and bright green leaves that give it a most attractive look. It is one of the most commonly found Philodendron species and can grow into a medium-sized plant variety.

Philodendron Radiatum Care

To grow Philodendron radiatum maturely at home is to grow it in indirect bright light. Keep a delicate balance between overwatering and underwatering this plant. You can feed your plant with the nutrients it needs in three ways.

– Water Requirements

The water needs of a Philodendron are simple. Its soil needs plenty of water each time you water it but it should be allowed to dry partially in between. Otherwise, there is a slight risk of developing fungal root rot. For beginners, if the top two inches of the soil are bone dry, you need to water the plant as soon as possible.

There are several ways to determine if the top two inches have dried. The most accurate result is given by a moisture meter if you happen to own one. You can also subjectively feel how dry the soil is by pushing your finger two inches down into it. A toothpick can also be inserted and taken out to see if dry crumbs are attached to it.

Philodendron needs plenty of water

As for using copious water, it should be approximately double the volume of the plant’s pot. Take special care not to let water splash onto the stems and leaves. Use a screen to protect them in case you can’t help making a bit of a mess. No matter how busy you are, you must always take at least five minutes to pour water slowly onto the soil.

Distilled water grows the healthiest Philodendrons. The salts and minerals in tap water will be collected in the soil and altered chemically. They will make it difficult for the roots to absorb water and nutrients. If using distilled water is not an option, use filtered or rainwater but refrain from using tap water at all costs.

– Light Requirements

The radiatum Philodendron cannot tolerate exposure to direct sunlight. Its leaves will suffer and become sunburnt. You will notice they are stiff, dry, and brown at the edges. Never keep them in the garden or near a south-facing window without proper shade.

Outdoors, a shaded area under a tree or patio would work. A north-facing wall also tends to block direct rays of sunlight. You can install a proper shade to protect your plant if you want to.

The chances of sunburn decrease inside the house except for a south-facing window. You will have to cover the window with sheer curtains.

The windows that face east and west also receive direct light for some time during the day. Early morning sunlight from the eastern window is tolerable. The mid-afternoon light from the western window will have to be filtered out. That is why we like placing our plants in corners of brightly lit rooms far away from windows.

On the other hand, low light conditions are also unhealthy and might cause the Philodendron radiatum variegated plant to lose its variegations. LED grow lights installed five to eight inches above the plant provide just the right amount of energy as this plant needs. They are quite economical so don’t worry about the extra expense.

– Soil Requirements

The best soil for Philodendron is one that you make at home. Buy equal quantities of peat and perlite and mix them as thoroughly as possible.

This plant likes its soil to be slightly acidic; you can check this using litmus paper. Add more peat or a little compost to make the soil acidic if it isn’t already.

– Temperature Requirements

A philodendron likes a temperature range of 55 to 80 degrees Fahrenheit no matter what time of the year. This is not a frost-hardy plant and must be protected from temperatures below 50 degrees.

You can grow it outdoors if you like, but you must bring it indoors once temperatures start falling at the end of summer.

Inside the house, too, you must keep it from very cold air drafts from the air conditioner or vent.

– Humidity Requirements

More than 60 percent humidity is needed to grow Philodendron leaves to their full size. Take help from a hygrometer to see how humid the air is within your living space. Humidity in most areas of the US falls within an average range of 35 to 50 percent. It will be slightly more in certain areas such as the laundry room and the kitchen.

You have the option of misting the leaves, using a pebble tray or a humidifier. Outdoors if you have a lot of humidity-loving plants, you can move them all together without compromising airflow. This automatically improves humidity around all these plants.

Mist the leaves only in the mornings before noon and twice a week. The leaves should only glisten lightly after misting and should not be wet. Otherwise, they will get infected with mildew disease.

humidity is needed to grow Philodendron leaves

You can also place a tray filled with water and pebbles under the Radiatum’s pot. Place large-sized pebbles in this tray for the pot to rest on. Just take care that the pot itself isn’t touching the water. In that case, the water from the tray will be absorbed into the soil and cause overwatering.

If you have an extra room to spare in the house, you can use a humidifier. Put your Philodendron and other humidity-loving plants in that room and turn the humidifier on. You can also use a humidifier in another room if you are comfortable with levels as high as 60 to 70 percent.

– Fertilizing Requirements

One way to fertilize a Philodendron is by using a slow-release type of fertilizer that comes in the form of pellets. All you have to do is to bury these pellets in the soil according to the instructions given on the label. Do this once at the start of spring and once in the middle of summer. Slow-release formulae work slowly but are safer, and you will also not need to fertilize every month.

If you can stick to the commitment of fertilizing every month, then go for a liquid type of fertilizer. It has the advantage that your plants will get an instantaneous boost of nutrients. Still, double or triple dilute the fertilizer and deep water the plant every time before use. These small acts of caution help a lot against chemical burns.

If you make your own compost, that can also be added to the soil. Add a handful of this compost to the soil while mixing it. When planting radiatum in the soil, add a little compost in the hole first and then put in the plant. If you rely solely on organic fertilizer, add it within the top layers of the soil every second or third week at the least. 

– Pruning

Pruning makes a plant grow faster and better. Choose your instrument well. Philodendron stems can be cut using pruning shears or a knife. Shears provide more control and make neat cuts in the stems.

Cut off the growing ends of the stems at 45 degrees to promote further growth. Pruning is your chance to get rid of any plant part that is old or diseased. Getting rid of very old and yellowing leaves helps open up nutrients to the newer stems and leaves. It also makes the plant less bushy, so air can flow through the inner stems.

Look closely at the parts under the large leaves and from where two stems branch. You might be able to catch pest infestations early on. Pruning can best be carried out any time during the spring-summer time.



We always urge our readers to propagate their houseplants during spring and summer. In fact, why not make it a yearly tradition with your friends and family?

– Stem Cutting Propagation

Stem cutting propagation is how we have been propagating this plant for years now. We don’t think anyone can go wrong with this simple technique:

  1. It is important to have meticulously disinfected pruning shears before cutting the stem. We let ours soak in 70 percent alcohol for 10 minutes and then wash them before use.
  2. Your cutting should be five to six inches long and come from the healthiest stem in the plant. It also needs to have two leaf nodes from which you can remove the leaves.
  3. You can put this cutting directly in the soil or grow the roots in water first.Stem Cutting Propagation Method
  4. For water propagation, take any transparent container or jar with a lid. Fill it with filtered water for the most fantastic results.
  5. Place your cutting inside, put the lid on and place the container somewhere bright. 
  6. It will take at least three weeks for new roots to grow. In the meantime, change the water inside every fifth to the sixth day.
  7. When you can see that the roots are long enough, plant the lower one-third of the cutting along with the roots in the center of a small pot.

– Air Layering Propagation

This method allows you to propagate a new root first before taking a cutting. You can then, later on, cut the part with the roots and plant it in the soil.

  1. Select one of the thickest stems in the plant for layering. Make a very shallow cut on this stem right underneath a leaf node around two to three inches long.
  2. Push something non-degradable inside the cut, such as a toothpick. This way, it will not heal up until roots grow from it.
  3. Remove the leaves from this and the next nearest leaf node. Wrap well-soaked sphagnum moss all around the diameter of the stem. Insert a straw in the moss to create a passageway for the airflow.
  4. Secure moss on the stem using a transparent plastic wrap and a few strings.
  5. Remove this outer covering every third to fourth day and sprinkle water on the moss to keep it moist and humid. Check the progress of new roots and wrap the whole thing up as before.
  6. It might take three weeks for the roots to emerge and become long enough. Cut the stem an inch from where roots are growing and plant it in a pre-prepared soil mixture. 

– Seed Propagation

Seed propagation is the easiest to carry out but be ready because many of your seeds might not germinate.

  1. You can use any shallow tray for germinating the seeds at home. Order your seeds from a seller you trust who has good reviews.
  2. You can use any growth medium to put the seeds in. We love using sphagnum moss that has been soaked in water for one hour and then strained thoroughly.
  3. Don’t bury the seeds completely in the moss because they need access to light. Instead, gently press them in the soil only. Keep a distance of half to one inch between each Radiatum seed.
  4. Put your seed under the indirect sun and keep sprinkling water on the moss. You should cover the tray with a transparent plastic sheet if your house is a bit dry.
  5. The seeds take about a month to germinate and then another month to grow enough to be transplanted.


Philodendron plants easily succumb to pest attacks when grown at home. You must know all the tricks to eliminating houseplant pests such as mealybugs, thrips, and scale insects. Besides these common problems, you will find Radiatum a most unproblematic plant.

– Mealybugs

A mealybug infestation cannot go unnoticed by an attentive plant parent. They are round and white houseplant pests that increase after using an infected tool. They also jump quickly from one plant to the next, spreading the infestation to all your houseplants.

They puncture the skin of the plant and feed on its sap. Then they release their sticky digestive juice all over the plant.

mealybug infestation

Not only can you see and feel this awful sticky substance, but it also attracts mold, dust, and flies to the leaves. Soon enough, your plant will look sick, yellow, and wilted.

Isolating the infested plant for 14 days is the first step. The second is giving it a thorough bath using water and a bar of mild insecticidal soap. Scrub under the leaves especially, using a toothbrush. For the next four weeks, use a mild organic pesticide spray once weekly to ensure the infestation is 100 percent cured.

– Thrips

Thrips cause the Philodendron leaves to become mottled with silvery-white discolorations. This alone can help you identify an infestation in progress. Over time, they suppress flowering and further growth of new leaves, stems, and flower buds. If you wiggle your plant a little, they will begin to fly around in large numbers.

One way to control their population is by using sticky yellow paper. Thrips are attracted to the color yellow, will land on this paper, and become trapped. You can then discard them easily. Their eggs and larvae can be removed by washing the plant and directing a pressurized beam of water under the leaves and towards stem joints.

For minor infestations, we suggest you do not resort to using chemical insecticides. They are harsh on the plant and lead to resistance. Instead, make a DIY foliar spray using kitchen items such as vinegar, baking soda, or neem oil. These natural treatment options are just as effective as chemical ones, if not better.

– Scale Insects

Scales are another variety of sap-sucking house pests you will have to deal with. They, too, secrete the sticky digestive juice called honeydew and attract mold to the leaves. Other symptoms of a scale infestation are similar, such as leaf yellowing, wilting, and growth retardation.

The downside is that scales are very small and immobile with shell-like bodies. They hide well under leaves and stem sheaths. Removing them physically is difficult.

We take a coarse bristle toothbrush and scrub the plant with it. This usually gets rid of most of the scales. At the same time, use water mixed with an insecticidal soap to wash the plant thoroughly. After this, use natural remedies like neem oil or baking soda every week for the whole of the next month to kill every last scale and its larvae.

– Overwatering

Overwatering is a big issue with a Philodendron plant. It cannot tolerate prolonged overwatering. Its large, firm leaves will swell, become mushy, and turn yellow.

It would be best if you found out why your soil is retaining all this extra water. You might be watering this plant excessively without any break for the soil to dry. Maybe the drainage of the potting mix or the container has been compromised somehow.

Suppose the drainage holes at the bottom of the container are inadequate or blocked, then open them up again. Mix a new and well-draining potting mix and repot the Philodendron in that one. Don’t forget to throw out the water collected in the drip tray right after watering. Lastly, get into the habit of always checking your soil before watering.


– Is Philodendron Radiatum Rare?

While not a rare species you will probably find it difficult to find online or even in plan nurseries. 

– Is Philodendron Radiatum a Climber?

Yes, it is. It is vigorous in its growth, has aerial roots and evergreen climbing philodendron

Philodendron Radiatum a Climber


Before signing off, let us recap the essence of all that we have learned today.

  • Radiatum can grow from low to partial bright light but never under direct light.
  • Water regularly and copious amounts of water, but only if the topsoil becomes dry enough.
  • More than 60 percent humidity is needed, or the large Philodendron leaves might start getting brown around the edges.
  • A philodendron likes a temperature of 55 to 80 degrees Fahrenheit no matter what time of the year.

With our easy-to-follow guidelines, you can grow this plant without much effort. The next time you see a Philodendron radiatum for sale anywhere, be sure to buy one for your home or office without hesitation.

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