Philodendron lupinum, an arum from the Amazon rainforests, captivates with its distinctive foliage. Its velvety, heart-shaped juvenile leaves mature into larger, glossy, and often corrugated forms. As a hemiepiphyte, it begins in the tree canopy before sending roots to the forest floor. Its unique aesthetic appeal and changing leaf morphology make it a fascinating addition to any indoor plant collection.
Understanding Philodendron Lupinum’s Needs
Light Requirements
Philodendron lupinum thrives in bright, indirect light, mimicking its natural habitat sheltered by the tree canopy. Providing between 2,500 to 10,000 lux is ideal for its growth. Place the plant near an east-facing window or a few feet from a south or west-facing window with filtered light. Direct sunlight can scorch leaves. Insufficient light can lead to slower growth, loss of vibrant leaf coloration, and leggy development.
Watering Practices
Maintain consistent soil moisture, but avoid waterlogging. Use the “finger test”: water thoroughly when the top inch or two of soil feels dry. This ensures adequate hydration while preventing root rot. Overwatering suffocates roots and causes yellowing leaves; underwatering results in drooping or crispy foliage. Adjust watering seasonally, increasing frequency during warmer growing months and reducing it in cooler, dormant periods.
Soil Mix
A well-draining, airy potting mix prevents water retention around the roots. Naturally, it often starts in tree bark before rooting in the ground. A suitable blend includes one-third potting soil, one-third orchid bark, and one-third perlite, or 100% sphagnum moss. This composition ensures proper aeration and drainage for root health. The ideal pH for the soil is mildly acidic to neutral, ranging from 6.5 to 7.
Temperature and Humidity
Philodendron lupinum flourishes in warm, humid environments, reflecting its tropical origins. The preferred temperature range is 63 to 80°F (17 to 27°C). Humidity levels are important, with an ideal range of 60-80% for optimal growth. Increase humidity using a humidifier, grouping tropical plants, or placing the pot on a pebble tray. Low humidity can lead to dry leaf tips and curling.
Fertilizing
During spring and summer, Philodendron lupinum benefits from regular fertilization. Apply a balanced liquid fertilizer (e.g., 20-20-20 or 10-5-5) once a month. Dilute the fertilizer to half strength to prevent nutrient burn. Apply fertilizer to moist soil, a few inches from the plant’s crown, for proper absorption and minimal stress. Stop fertilization during fall and winter when growth slows.
Maintaining Your Philodendron Lupinum
Repotting
Repot Philodendron lupinum every two years or when it shows signs of being root-bound. Indications include roots emerging from drainage holes, circling the pot, or water running straight through the soil. Choose a pot only one size larger to avoid excess soil retaining too much moisture. Gently remove the plant, inspect roots for unhealthy sections, and loosen the root ball before placing it in fresh, well-draining potting mix.
Pruning and Support
Pruning helps maintain its shape, encourages bushier growth, and removes dead or damaged foliage. The best time for major pruning is late spring or early summer, at the start of its growing season. Make clean cuts just above a node, where new growth emerges. As a vining plant, it benefits from vertical support like a moss pole or trellis. Support encourages larger, more mature leaves and helps establish healthy aerial roots, mirroring its natural climbing habit.
Propagating Philodendron Lupinum
Propagate Philodendron lupinum through stem cuttings, a straightforward method. Select a healthy stem with at least one node and one leaf. Make a diagonal cut just below a node. Remove any leaves that would be submerged in water to prevent rot.
The cuttings can be rooted in water or moist sphagnum moss. Place them in a warm, humid environment away from direct sunlight to encourage root development. Covering cuttings with a plastic bag (with ventilation holes) helps maintain higher humidity. Roots typically form within a month, after which new plants can be transferred to individual pots with appropriate soil.
Troubleshooting Common Problems
Common Pests
Philodendron lupinum can encounter common houseplant pests like spider mites, mealybugs, and aphids. Spider mites create fine webbing and cause tiny yellow spots on leaves. Mealybugs appear as small, fuzzy white masses, usually on leaf undersides or in leaf axils. Aphids are small, often green insects that cluster on new growth and leaf undersides.
For treatment, a strong stream of water can dislodge many pests. Apply organic solutions like insecticidal soap or neem oil to the foliage, ensuring both top and undersides are coated. Regular inspection and wiping leaves with a damp cloth help prevent and manage infestations.
Leaf Discoloration (Yellowing, Browning, Drooping)
Leaf discoloration often indicates an environmental imbalance. Yellowing leaves can signal overwatering (soil too wet, depriving roots of oxygen) or underwatering (dehydration). It can also indicate nutrient deficiencies or too much direct light. Adjusting watering practices by allowing the top soil to dry between waterings and ensuring proper drainage can resolve issues.
Browning leaf edges often point to low humidity or inconsistent watering; crispy brown leaves suggest underwatering. Drooping leaves can result from overwatering (leading to root rot) and severe underwatering. Address these symptoms by checking soil moisture, increasing humidity, and ensuring adequate, indirect light.
Slow Growth/Lack of Velvety Texture
Slow growth can be attributed to insufficient light, inadequate nutrients, or suboptimal temperature and humidity. The plant grows faster with bright, indirect light and warm, humid conditions. If the velvety texture of juvenile leaves appears diminished, it may be due to insufficient light affecting leaf development. Consistent, appropriate care for light, temperature, humidity, and nutrients will encourage vigorous growth and desired leaf characteristics.
Root Rot
Root rot is a serious condition characterized by mushy, dark roots and a foul smell from the soil. It primarily results from overwatering, where waterlogged soil suffocates roots and promotes fungal growth. Above-ground symptoms include yellowing, wilting, or drooping leaves, and mushy stems.
If root rot is suspected, carefully remove the plant from its pot and gently wash away old soil from the roots. Trim away affected, mushy, or discolored roots using sterilized scissors, cutting back to healthy, firm tissue. Repot into a clean pot with fresh, well-draining soil, and water sparingly until signs of recovery are observed.