Hi Shaden,

Here is some advice how to help your Philodendron Selloum grow better.

Light
Philodendron Selloums grow well in bright indirect lightVery few houseplants should be placed in direct sun. High light refers only to bright indirect light since direct sun often burns the leaves of indoor houseplants. An area that is too hot and dry encourages Spider Mites and causes blooms to quickly fade. A northern exposure really doesn't provide enough light for high light plants. These plants need to be placed directly in front of an east-facing window, within 1-3 feet of a west-facing window, and within 5 ft. of a south facing window. A high light area has over 300 ft. candles of light.. In lower light the leaves of a Philodendron Selloum turn a darker green. Direct sun or too much direct light burns or fades the leaves of a Philodendron Selloum.

Water
Unlike other Philodendrons, the Philodendron Selloum likes moist but not soggy soil. During the winter, water this Philodendron less often, keeping the soil barely moist.

fertilizerPlants need fertilizer only when they are actively growing. Slow growing plants in low light require very little plant food. Too much fertilizer is worse than not enough. Most plants prefer a water soluble plant food at 1/2 the recommended strength. Plants that are in bloom or dormant should not be fertilized. Houseplant food contains nitrogen (N), phosphorus (P), and potassium (K). A fertilizer containing these elements in equal proportion is considered a balanced plant food. Nitrogen helps in photosynthesis and encourages the growth of leaves and stems. Potassium and phosphorus also help in photosynthesis and aid in root and flower development. Most fertilizers have trace elements of other minerals that are lacking in the soil but are necessary for good plant growth. Fertilizers have a high salt content. If a plant is not producing new leaves and doesn’t absorb the fertilizer, salts build up in the soil. These salts can burn the roots, discolor the leaves, and cause new growth to be small.  
Feed a Philodendron Selloum with a water soluble fertilizerPlants need fertilizer only when they are actively growing. Slow growing plants in low light require very little plant food. Too much fertilizer is worse than not enough. Most plants prefer a water soluble plant food at 1/2 the recommended strength. Plants that are in bloom or dormant should not be fertilized. Houseplant food contains nitrogen (N), phosphorus (P), and potassium (K). A fertilizer containing these elements in equal proportion is considered a balanced plant food. Nitrogen helps in photosynthesis and encourages the growth of leaves and stems. Potassium and phosphorus also help in photosynthesis and aid in root and flower development. Most fertilizers have trace elements of other minerals that are lacking in the soil but are necessary for good plant growth. Fertilizers have a high salt content. If a plant is not producing new leaves and doesn’t absorb the fertilizer, salts build up in the soil. These salts can burn the roots, discolor the leaves, and cause new growth to be small.   monthly during the spring, summer, and fall. Dilute the plant food to 1/2 the recommended strength to avoid excess salts building up in the soil of a Philodendron Selloum and burning the leaves.

Temperature
Philodendron Selloums like to be warm so keep the temperature above 55 degrees during the winter.

Humidity
A Philodendron Selloum is a tree philodendron and has thinner leaves than many of its relatives, this is why it needs a more humid environment to flourish. If your house or office is very dry in the winter, place a Philodendron Selloum near a humidifier or on a wet pebble tray.

Flowering
It takes about 15-20 years for a Philodendron Selloum to flower and it rarely flowers indoors. The pedal-less flowers of a Philodendron Selloum are enclosed in a spathe, a modified leaf, which is often mistaken for the flower.

Pests
Plant insects such as AphidsSee a picture, learn to identify, and read about Aphid houseplant pests in the Glossary of Houseplant411.com., Mealy BugsLearn how to identify and treat Mealy Bugs, a houseplant pest that leaves sticky, white, cottony residue on houseplants., scaleSoft Brown Scale is the most common scale that attacks indoor houseplants especially ficus, ivy, spider plants, ferns, aralia, and schefflera. It appears as small bumpy brown spots that appear to move. As the scale sucks on the sap of the plant it secretes a sticky substance called honeydew. The honeydew attracts black mildew. Because of the shell-like exterior, sprays are only partially effective against scale. Wipe off the lines of brown oval bumps with your finger, a cloth, or a child’s toothbrush then spray the plant with Neem Oil. Use the Green Solution to clean off the black mildew., and spider mitesLearn how to identify and treat Spider Mites on plants. This sucking plant pest causes yellow blotchy leaves with a red haze and a gritty feel to them. can be a problem for a Philodendron Selloum. If your Selloum gets any of these pests, spray the entire plant with warm soapy water or the green solutionIf you don't want to use a commercial chemical product to treat plant pest problems try the “Green Solution.” This is a mixture of water, alcohol, biodegradable liquid soap, and mineral oil. Always test any spray on one or two leaves to be sure it won’t damage the plant. Depending upon how severe the infestation is, you can use these ingredients in varying proportions. If there are only a few pests, dip a Q-tip in alcohol and gently swab them off. For a more widespread problem, start by using a spray of warm water mixed with a few tablespoons of biodegradable soap. If that doesn’t cure the problem, make a solution using 8oz. water & 8oz. alcohol, add two tablespoons of biodegradable soap and two tablespoons of mineral oil. Spray all areas of the plant. Use this solution on leathery leafed plants (except palms), never on fuzzy leafed plants like African Violets or Begonias. For palms, omit the alcohol from the Green Solution. Never spray a plant that’s sitting in the sun or one with very dry soil.    . Scrape off scaleSoft Brown Scale is the most common scale that attacks indoor houseplants especially ficus, ivy, spider plants, ferns, aralia, and schefflera. It appears as small bumpy brown spots that appear to move. As the scale sucks on the sap of the plant it secretes a sticky substance called honeydew. The honeydew attracts black mildew. Because of the shell-like exterior, sprays are only partially effective against scale. Wipe off the lines of brown oval bumps with your finger, a cloth, or a child’s toothbrush then spray the plant with Neem Oil. Use the Green Solution to clean off the black mildew. with a children’s toothbrush.

Diseases
Bacterial Blight is a plant disease that infects a Philodendron Selloum causing small very dark green blotches on leaves which expand rapidly. Infected leaves eventually rot and die, becoming quite smelly in the process. The best way to prevent this plant disease from infecting your Philodendron Selloum is to keep the leaves dry at all times, avoid overhead watering, and immediately remove any infected leaves.

Soil
A Philodendron Selloum grows best in a rich, slightly alkaline soil that retains moisture. The leaf tips of a Philodendron Selloum burn when there is too much salt in the soil usually due to over-feeding.

Pot Size
Re-pot a Philodendron Selloum when it becomes pot-bound. You can tell it’s time for a larger pot when the roots take on the shape of the existing pot. The new container for the Selloum should be 1″-2″ wider and deeper than the previous container.

Pruning
Prune a Philodendron Selloum with sharp pruners to control its size and shape. You can cut entire leaves off of a Selloum at the base of the leaf stem. Remove lower leaves to reveal the plant’s stem. Wear gloves when pruning a Philodendron Selloum and wash your hands and tools when finished. All Philodendrons are very poisonousPlants are a great addition to homes and offices, but it’s important to know whether your plants are dangerous to children, pets, or even adults. Some plants contain chemicals such as oxalates, solanine, glycosides, or alkaloid lycorine that may cause vomiting, nausea, diarrhea, swelling and redness of the mouth, throat, and lips, and trouble breathing. Touching parts of certain plants, especially the sap, may cause various skin irritations. The weight and age of the human or pet involved, and the part and amount of plant eaten determine how severe the reaction to the toxins will be. Although plants may be listed as non-toxic, they can still cause individual allergic reactions. If there is any question after a houseplant has been ingested or touched immediately call the Poison Control Center 1-800-222-1222 The Handbook of Poisonous and Injurious Plants [Paperback]is an excellent reference to keep around if you have young children and pets. and you don’t want to get the sap in your eyes or mouth.

propagationLearn how to propagate plants by plant division at https://www.houseplant411.com/glossary
Philodendron Selloums are easy to propagate from stem cuttings. Dipping the cut end into a little Rooting HormoneRooting Hormone helps plant cuttings produce new roots and is very important to use if you want your propagation attempts to be successful. Always dip the cut end of a stem or leaf into water and then dip it into the rooting hormone before planting it. Tap off any excess powder since too much hormone is worse than too little. increases the chances of success.

poisonousPlants are a great addition to homes and offices, but it’s important to know whether your plants are dangerous to children, pets, or even adults. Some plants contain chemicals such as oxalates, solanine, glycosides, or alkaloid lycorine that may cause vomiting, nausea, diarrhea, swelling and redness of the mouth, throat, and lips, and trouble breathing. Touching parts of certain plants, especially the sap, may cause various skin irritations. The weight and age of the human or pet involved, and the part and amount of plant eaten determine how severe the reaction to the toxins will be. Although plants may be listed as non-toxic, they can still cause individual allergic reactions. If there is any question after a houseplant has been ingested or touched immediately call the Poison Control Center 1-800-222-1222 The Handbook of Poisonous and Injurious Plants [Paperback]is an excellent reference to keep around if you have young children and pets. Plant Info
A Philodendron Selloum is a very poisonousPlants are a great addition to homes and offices, but it’s important to know whether your plants are dangerous to children, pets, or even adults. Some plants contain chemicals such as oxalates, solanine, glycosides, or alkaloid lycorine that may cause vomiting, nausea, diarrhea, swelling and redness of the mouth, throat, and lips, and trouble breathing. Touching parts of certain plants, especially the sap, may cause various skin irritations. The weight and age of the human or pet involved, and the part and amount of plant eaten determine how severe the reaction to the toxins will be. Although plants may be listed as non-toxic, they can still cause individual allergic reactions. If there is any question after a houseplant has been ingested or touched immediately call the Poison Control Center 1-800-222-1222 The Handbook of Poisonous and Injurious Plants [Paperback]is an excellent reference to keep around if you have young children and pets. houseplant with a levelThese are general guidelines that describe how poisonous certain houseplants are. It's possible for an allergic reaction to occur from contact with any houseplant, toxic or non-toxic. If there is ever a concern, call: Poison Control Center: ******1-800-222-1222****** Level #1: Houseplants with low toxicity, may be mildly irritating, especially the sap of the plant. Level#2: Houseplants with medium to severe toxicity. Eating parts of these houseplants may result in vomiting, diarrhea, stomach pains, skin irritations, and breathing difficulties. Level #3: These houseplants are  very poisonous. When eaten, especially in large quantities,  severe vomiting, diarrhea, stomach pains, skin irritations, and breathing difficulties can occur. Level #4: These houseplants are extremely poisonous. Eating parts of these houseplants can be be life threatening. Every plant listed in our Popular HousePlant guide has a section explaining whether or not it is poisonous and, if so, how poisonous. Amaryllis, alocasia, dieffenbachias, crotons, ivies, azaleas, lilies, and philodendrons are just a few of the highly poisonous plants we use in our homes and offices all of the time. If you don't know whether your houseplant is poisonous, go to Ask Judy on the HousePlant411.com website, send her a picture of your plant, and she'll let you know if the houseplant should be kept away from small children and pets. See colorful pictures and get more information about poisonous houseplants in Don’t Feed Me To Your Cat! A Guide to Poisonous Houseplants   #3 toxicity. All Philodendron Plants are poisonousPlants are a great addition to homes and offices, but it’s important to know whether your plants are dangerous to children, pets, or even adults. Some plants contain chemicals such as oxalates, solanine, glycosides, or alkaloid lycorine that may cause vomiting, nausea, diarrhea, swelling and redness of the mouth, throat, and lips, and trouble breathing. Touching parts of certain plants, especially the sap, may cause various skin irritations. The weight and age of the human or pet involved, and the part and amount of plant eaten determine how severe the reaction to the toxins will be. Although plants may be listed as non-toxic, they can still cause individual allergic reactions. If there is any question after a houseplant has been ingested or touched immediately call the Poison Control Center 1-800-222-1222 The Handbook of Poisonous and Injurious Plants [Paperback]is an excellent reference to keep around if you have young children and pets. if ingested and the sap may irritate the skin.