Red Emerald (Philodendron erubescens "Red Emerald") is a hybrid philodendron with attractive foliage. The leaves are red when new, turning a shiny dark green in maturity. The undersides may have a coppery tinge. Even Red Emerald's stems, or petioles, are red. It climbs to 60 feet in the rainforest but, in cultivation it remains near 12 feet in height. Red anthuriumlike flowers round out the show when you grow Red Emerald philodendron.
Light and Temperature
Red Emerald philodendron thrives when temperatures are between 70 and 90 degrees Fahrenheit and declines when they dip below 60 or climb over 95 degrees. For the best color, grow Red Emerald philodendron in high light. Growers, who measure light in foot-candles, suggest that, for the best color, provide Red Emerald with 150 foot-candles of light. This is comparable to what you find in a typical American classroom, with overhead fluorescent lighting.
Red Emerald is a rainforest plant and requires lots of humidity. Place a humidifier in the room where you grow the plant, or mist it frequently throughout the day with water from a misting bottle. It is especially important to keep the air moist if you run a furnace or air conditioner. Keep the planting medium moist at all times, applying more water when the weather is hot and cutting back when it cools off.
Grow the Red Emerald philodendron in a fast-draining potting soil. Make your own with equal parts of potting soil, peat moss, perlite and orchid bark. When shopping for orchid bark mix, choose one that contains charcoal and gravel. When you transplant the larger Red Emerald that requires a 3-foot tall or taller stake, coarse sand should make up at least 20 percent of the potting mixture to keep the stake upright.
Don't fertilize the philodendron when you first bring it home, but wait until it puts out new growth. Use a fertilizer with a 3-to-1-to-2 ratio of nitrogen, phosphorus and potassium, such as 15-5-10 according to the amount listed on the fertilizer label. Reapply the fertilizer monthly. Once a month, leach the soil of fertilizer salt buildup. These salts can cause burn marks on the leaves and damage the Red Emerald's roots. The best place to leach the soil is in the bathtub or outdoors, with a hose. Slowly pour water over the soil until it runs from the bottom of the pot. When it drains, repeat the procedure two more times.