The “planta pene” is a common name for Amorphophallus konjac, a unique perennial known for its distinctive appearance and fascinating life cycle. Its unusual characteristics make it a compelling addition to any plant collection, sparking widespread interest among gardeners and plant enthusiasts.
Understanding the “Planta Pene”
The plant commonly called “planta pene” is Amorphophallus konjac, also known as Voodoo Lily, Devil’s Tongue, Konjac Plant, and Elephant Foot Yam. Its common name comes from the phallic shape of its inflorescence, specifically the spadix. The plant emerges from a subterranean corm, which can grow quite large.
Its dramatic bloom features a dark maroon to purple spathe (a leaf-like bract) that enfolds a pale green to purple spadix. This striking flower can reach up to 3 feet tall. After blooming, a single, large, umbrella-like leaf emerges, often mottled with pinkish-gray and olive-green markings. The flower emits a potent, carrion-like odor to attract pollinators like flies and beetles; this smell typically lasts only a few days.
Caring for Your “Planta Pene”
Light
Amorphophallus konjac thrives in bright, indirect light. While it tolerates some direct morning sun, protect it from harsh afternoon sun to prevent scorching. Indoors, an eastern or western facing window is suitable.
Soil
A well-draining, rich, humusy potting mix is ideal. The soil should retain moisture but never become waterlogged to prevent corm rot. Incorporating organic matter like well-rotted leaf compost enhances fertility and drainage.
Water
Maintain consistent moisture during the active growing season, from leaf or flower emergence until foliage browns in autumn. Allow the top half of the soil to dry out between waterings to prevent overwatering. During dormancy, reduce or stop watering entirely.
Temperature and Humidity
Amorphophallus konjac prefers warm temperatures (68-77°F / 20-25°C) and high humidity, reflecting its subtropical and tropical origins. While the corm is hardy in USDA Zones 7-10, the leaf and inflorescence are sensitive to frost.
Fertilizing
During its active growth phase, Amorphophallus konjac benefits from regular fertilization. A balanced fertilizer, such as a 10-10-10 NPK ratio, applied every 4-6 weeks, can support healthy development. Fertilizing should cease once the plant enters its dormant period.
The Unique Life Cycle of “Planta Pene”
The life cycle of Amorphophallus konjac begins with a dormant period, where the plant exists as a corm—a bulb-like underground storage organ. As temperatures rise in late spring to early summer, the corm breaks dormancy, often producing its flower before any foliage emerges.
After the bloom fades, a single, large, umbrella-like leaf develops from the corm. This leaf conducts photosynthesis throughout the growing season, gathering energy to enlarge the corm. As autumn approaches and temperatures cool, the leaf yellows and dies back, signaling the plant’s return to dormancy. The corm then rests, storing energy for the next growth cycle.
During dormancy, the corm can remain in its pot in dry growing medium or be removed and stored in a cool, dry place like peat moss. Keep corms dry to prevent rot, typically at temperatures around 42-50°F (5-10°C). Repotting should occur during this dormant phase, every 2-3 years or when the corm outgrows its container, transferring it to a slightly larger pot with fresh soil.
Common Issues and Important Notes
Corm rot is a common problem, primarily caused by overwatering or poorly draining soil during active growth or dormancy. Ensure the soil dries out between waterings and provide a well-aerated potting mix to prevent this. Failure to sprout after dormancy can occur if corms are stored in conditions that are too cold or too wet.
Amorphophallus konjac contains calcium oxalate crystals, making all parts toxic if ingested raw. These crystals can cause irritation to the mouth, throat, and digestive system. Keep the plant away from pets and small children. Propagation is often achieved through offsets, or cormels, which naturally form from the parent corm and can be separated during dormancy.