The Philodendron Rojo Congo is a stand-out among philodendron plants. While most of its relatives grow as climbing vines, the Rojo Congo grows upright with massive dark green to reddish-purple leaves. But this beauty can be hard to find and moderately difficult to care for.
Philodendron Rojo Congo requires large pots with well-draining yet moisture-retaining soil. The house should have humidity above 50% and temperatures between 65–85° F (18–29° C). Common problems involve getting the right balance of bright indirect light and watering below the foliage.
Here is a guide on the Philodendron Rojo Congo and how to keep one healthy so it’s a beautiful addition to your home.
What is the Philodendron Rojo Congo
The Philodendron Rojo Congo comes from the Araceae family, of which philodendrons are the second to largest genus.
Marian Wincenty Osiecki of Oglesby Plants International, Inc. in Altha, Florida, patented the Philodendron ‘Rojo Congo’ in 1996. It is a cultivar crossed between the Philodendron tatei ssp. Melanochlorum’ Congo’ and the Philodendron erubescens’ Imperial Red’.
Philodendron Rojo Congo has more red in its leaves than Imperial Red. It is smaller and has narrower leaves than the Congo.
Most nurseries with this plant are in Florida and South America. But the plant has also escaped households and naturalized in the Philippines, South Africa, and Australia.
Growth Habit and Size
Most philodendrons prefer to climb and, in the wild, use trees to support and reach more light. Individual plants vary, but Philodendron Rojo Congos often grow as bushy self-headers or arborescent. They stand on their own like a tree rather than lean on the environment for support.
Leaves also emerge close together from one main stem. From above, the leaves form a rosette shape. Outdoor plants lose a denser, bushy shape for a leggier one.
Indoor Philodendron Rojo Congos will slowly grow up to 2 ft (61 cm) tall and 2.5 ft (76 cm) wide. Outside in tropical yards, they will grow faster and more massive.
Leaves and Flowers
The Philodendron Rojo Congo has leathery, ovate leaves up to 12 inches (30 cm) wide and 18 inches (45 cm) long. Young leaves will have a lighter green, while mature leaves will be dark and with green-brown to purple undersides. The margins range from brown to red, the midrib is light green, and the petioles have a rich dark purple.
Philodendron Rojo Congo achieves reddish hues thanks to anthocyanin, a molecule the leaves produce. It takes lots of energy for the plant to make anthocyanin.
But with green chlorophyll, anthocyanin makes the leaf appear dark. It hides from foraging animals and attracts pollinators. The Philodendron Rojo Congo inherited this trait from wild predecessors.
Leaf angle depends on where they exist on the plant. Upper leaves grow pointing more vertically compared to the more horizontal lower leaves. New leaves come out furled.
Indoor philodendrons rarely bloom. But if the Rojo Congo develops flowers, the blooms are small, white clusters.
Like other philodendrons, the Rojo Congo grows best in bright but indirect light. It tolerates darker areas far from windows and burns if it gets too much direct light.
The reddish colors develop best in bright light. A northern exposure or window sheers will help you achieve the right balance for your plant. The other color contrasts, like lighter midrib and darker leaf topsides, also do best in the brightest indirect light.
Philodendron Rojo Congos pose a moderate challenge when it comes to watering. They like moist but not soggy soil. If you stick your finger into the first 2 in (5 cm), and if it feels dry, it’s time to water. You can also use a stick and see if it darkens or has soil sticking to it, indicating moisture.
Add room-temperature water at the base to avoid wetting the foliage. Keep adding the water until it starts to exit through the drainage holes. That way, you know that the soil is evenly moist.
If you haven’t watered in a while, the leaves may have dry edges. Too much water can shock the plant. You will want to lightly water and then ease into your old routine.
Temperature and Humidity
As tropical rainforest plants, Philodendron Rojo Congos love warm temperatures. They do best at 75–80° F (24–27° C) but tolerate 65–85° F (18–29° C). If you are in a region where you can grow them outdoors, they grow in USDA Hardiness Zones 9b–12.
Rainforests are also humid, and you’ll want to imitate that as much as possible. Philodendron Rojo Congos grow best above 70% humidity, but they will be happy at typical household levels at 40–60%. You can use a humidifier or spray and wipe down the leaves twice a week if your home lacks the right level. Avoiding drafts and using more organic material in the soil also helps.
The Philodendron Rojo Congo is an aroid plant. It likes lots of air around its roots. Well-draining soil is a must to imitate a rainforest life where a philodendron would be clinging to a steep surface with minimal soil.
It also needs lots of moisture. Soil mixes rich in organic and aeration materials like perlite, vermiculite, orchid bark, and peat moss work the best. These mixes also provide the ideal 5.6–7.5 neutral to acidic pH. You can also buy aroid and cactus pre-made mixes.
This cultivar can grow large, so it will eventually need a large pot, like 15–18 inches (38–46 cm). Terracottas provide stability for heavier plants and wick moisture if you tend to overwater.
If you notice the roots trying to escape the soil, it’s time to repot. You’ll see them popping up on the surface or down through the pot’s drainage holes. Young plants need this about once every two to three years, with the next pot 2 in (5 cm) in diameter larger than the last.
Even if you have a mature plant, repotting is an opportunity to place it in a fresh, nutritious soil mix. Give it a few weeks to overcome the shock from the transition.
Otherwise, Philodendron Rojo Congos like a root-bound, snug fit in their pots.
The Philodendron Rojo Congo is sensitive to chemical fertilizers. Using organic-rich soil mixes helps with nutrition, but also it’ll absorb and slowly release any chemical fertilizer you add.
Apply liquid fertilizer a few months apart after watering in the spring and summer. You can also use a slow-release fertilizer once in the spring and once in the summer.
When you pick a fertilizer, go with a brand with one of two ratios. Go for a balanced ratio of nitrogen (N), phosphorus (P), and potassium (K), or a higher ratio for nitrogen and lower in phosphorus. For instance, the NPK ratio could be 3:1:2.
Nitrogen supports the overall size and green growth. Phosphorus goes to the roots, and potassium helps cellular function. But phosphorus also goes to flowers and seeds, which your Philodendron Rojo Congo won’t need indoors.
Whatever amount the instructions tell you to use, dilute it to a ⅓ or a ¼. This rule works well with indoor plants. They grow slowly, so they don’t need as much fertilizer at once.
The Philodendron Rojo Congo also needs calcium and magnesium supplementation. You can use boiled crushed eggshells for calcium and Epsom salt for magnesium.
You can propagate Philodendron Rojo Congo cuttings, but not as readily as other philodendrons. Climber philodendrons have more nodes with aerial roots that are easy to propagate. Self-headers like Rojo Congos have fewer of these.
If you find a suitable segment, cut about ½ in (1.25 cm) below the node. Place the new stem in a clear container of water in an area with indirect bright light. Change the water every so often, and the cutting will grow in 6–8 weeks.
Once the roots are 1 inch (2.5 cm) long, you can transfer the cutting to well-draining soil in a small pot, like 6 in (15 cm) in diameter. Water frequently for the next few weeks so the soil is always moist.
If your mature Philodendron Rojo Congo has a secondary set of leaves coming up through the soil apart from the main leaves, you can propagate by division. The offshoots have a separate root ball you can tease free from the main plant and place in a new pot.
Thick stems like those of the Philodendron Rojo Congo can also be propagated by air layering. This method is like regular cutting. You find the aerial roots at the nodes and cut below.
But instead of submerging it in water, you place the cut section against damp moss and wrap both in a clear plastic bag. Secure it and poke a few holes. Periodically, you spray the bag so that the moss retains some moisture. After 3–5 weeks, roots will grow, and you transfer the new Philodendron to a pot like a regular cutting.
Propagation works best in the spring and summer when the plant is an active grower.
The Philodendron Rojo Congo leaves tell you what problems the plant suffers. Whether you overwater, underwater, or got too much cold draft exposure, the leaves reflect the issue.
- Pale leaves: Not enough light, particularly if the leaves grow from leggy petioles. A few pale leaves on an otherwise dark plant indicate cold exposure or magnesium deficiency.
- Yellow leaves: Overwatering or not enough soil aeration. Water the Philodendron less or repot with a soil mix with better aeration.
- Brown spots on leaves: Too much direct light. Provide the Rojo Congo with some shelter.
- Spotted leaves: Fungal infection from overwatering or too much humidity. Adjust these factors and prune the infected leaves.
- Dark spots on leaves: Contact with cold, such as a window. Move the Philodendron away.
- Shriveled green leaves: Usually underwatering, but sometimes the Rojo Congo needs more light.
- Clear spots with yellow rims on leaves: Xanthomonas infection. Stop overhead watering and prune infected leaves.
- Dark green, mushy spots on leaves and petioles: Erwinia infection. Stop overhead watering and prune infected leaves.
This Philodendron also suffers from diseases, aphids, mealybugs, Erwinia bacteria, and Xanthomonas bacteria.
- Aphids: Apply insecticidal soap or neem oil once per month for prevention. Once they establish, they are hard to eradicate. Blasting with water or wiping down leaves also helps.
- Mealybugs: Treat them like aphids. Rubbing alcohol also works.
- Xanthomonas and Erwinia: If pruning and stopping overhead watering isn’t enough, isolate the Philodendron Rojo Congo in an area with good circulation. Then repot it in a better-aerated soil mix and prune the infected leaves.
You can also make insecticidal soap with a teaspoon of plain, unscented dish soap with a gallon of water. When applying any insect treatment, make sure you pay close attention to the undersides of the leaves.
The Philodendron Rojo Congo is a middling challenge to care for. But encouraging its size and colors makes an effort rewarding.
Keep an eye on the growth rate and the roots. Slow-growing Philodendron Rojo Congos need more fertilizer. It’s also a good time to check if the roots are trying to escape. If so, you can solve the slow growth by putting the plant in a larger pot with fresh soil.