The Devil’s Tongue Plant, Amorphophallus konjac, offers a unique and intriguing presence for plant enthusiasts. This exotic perennial grows from a large subterranean corm and displays a single, highly divided leaf with a striking mottled stem, giving it an umbrella-like appearance. While its foliage is distinctive, Amorphophallus konjac is most renowned for its unusual flower spike, which, when mature, can emit a strong, often malodorous scent resembling rotting flesh. Its unique bloom and impressive leaf make it a captivating addition.
General Care Essentials
Successful cultivation relies on specific environmental conditions during its active growing season (spring through fall). Consistent attention to light, soil, water, temperature, humidity, and fertilization promotes robust growth.
Light
During its active growth phase, Amorphophallus konjac thrives in bright, indirect light. An east or west-facing window is ideal, or a south-facing window in winter. Avoid prolonged direct afternoon sun, as intense light can scorch foliage.
Soil
The ideal soil for Amorphophallus konjac is well-draining and rich in organic matter. A suitable mix includes peat moss, perlite, and compost for aeration and moisture retention. This plant prefers slightly acidic to neutral soil, with a pH between 6.0 and 6.5. Good drainage is essential to prevent waterlogging, which can lead to corm rot.
Water
Consistent moisture is important during its growing season. Water the plant regularly, ensuring the soil remains evenly moist but not saturated. Before rewatering, allow the top 1-2 inches of soil to dry out. Avoid standing water, as overwatering can lead to root issues.
Temperature and Humidity
Amorphophallus konjac prefers warm temperatures (68-77°F / 20-25°C) during active growth. It can tolerate a minimum of 60°F (16°C). Moderate to high humidity (50-60%) is beneficial. To increase humidity, consider using a pebble tray or a room humidifier.
Fertilizer
During the growing season, it benefits from regular fertilization. Apply a balanced liquid fertilizer (e.g., 10-10-10) or a phosphate-rich formula (e.g., 15-30-15) every 4-6 weeks. This consistent feeding supports the development of a healthy corm and lush foliage.
Navigating the Dormancy Cycle
Amorphophallus konjac exhibits a distinct annual dormancy period, crucial for its long-term health. As autumn approaches, the plant’s single leaf will begin to yellow and eventually die back. This signals its resting phase.
Once the foliage has completely browned and withered, watering should cease entirely. During dormancy, the corm can either remain in its pot with dry growing medium or be carefully removed, cleaned, and stored. If storing outside the pot, place the corm in a cool, dry, dark location (40-50°F / 5-10°C), often in dry peat moss or wood shavings, ensuring good air circulation. The corm should be kept dry to prevent rot. As spring approaches, the corm will sprout new growth, signaling the end of dormancy and the start of a new growing season.
Repotting and Propagation
Repotting is best done during dormancy or just before new spring growth. Choose a pot at least twice the corm’s diameter for ample root space. When repotting, refresh the soil with a well-draining, organic-rich mix.
Propagation is commonly achieved by separating cormels that form around the main corm. These smaller corms can be carefully detached from the parent plant during dormancy. Each cormel can then be planted individually in its own pot with suitable soil. Propagation from seed is possible but less common for home growers due to complexity and time to maturity.
Troubleshooting Common Problems
Most common issues can be addressed with proper care.
Yellowing leaves often indicate overwatering or underwatering, which stress the plant and impair nutrient uptake. Insufficient nitrogen or other nutrient deficiencies can also cause foliage to yellow. Adjusting watering practices and ensuring balanced fertilization can resolve these issues.
Corm rot is a significant concern, typically caused by excessive moisture and poor drainage, especially during dormancy. Ensuring well-draining soil, allowing it to dry between waterings during the growing season, and completely drying the corm during dormancy helps prevent this.
A lack of growth or flowering can stem from insufficient light, improper dormancy care, or an immature corm. Larger, mature corms (about the size of a grapefruit) are more likely to produce a flower spike.
While generally robust, it can occasionally be affected by common houseplant pests like mealybugs or spider mites. Regular inspection and organic pest control methods, such as insecticidal soap, can manage infestations.
It contains calcium oxalate crystals, making it irritating if ingested. All parts of the plant, especially when raw, can cause discomfort in the mouth and throat. Keep the plant out of reach of pets and children.