The Devil’s Tongue Plant (Amorphophallus konjac) is a perennial that grows from a large, subterranean corm. It is primarily known for its striking, single leaf, which can resemble a small tree, and its brief, malodorous bloom. The name “Devil’s Tongue” refers to the flower’s appearance and its infamous scent, which attracts carrion-feeding insects for pollination. The plant follows a distinct seasonal life cycle, emerging from dormancy in the spring to produce foliage before dying back completely in the fall.
Essential Environmental Needs
Successful cultivation requires an environment that mimics its native subtropical habitat. Planting should occur in the spring, after the threat of frost has passed and the soil temperature remains above 60°F. Since the roots emerge from the top of the corm and grow horizontally, the corm must be planted deeply—about the same distance below the surface as the corm’s diameter.
Containers must be deep and wide, as the corm grows significantly each season and requires space for its spreading root structure. The soil mixture must be rich in organic matter, fertile, and provide excellent drainage. While the plant needs moisture during active growth, heavy clay soils or mixes that retain too much water are unsuitable and can lead to corm rot.
The plant thrives in dappled shade or bright, indirect light, mimicking its natural understory environment. Shield the foliage from intense, direct afternoon sun, especially when the leaf first emerges, to prevent scorching. During the active growing phase, the optimal temperature range is 68°F to 77°F, though the plant tolerates temperatures down to 60°F.
Routine Care During the Growing Season
Once the single leaf unfurls, the plant enters a period of intensive growth requiring consistent maintenance. Maintain consistent soil moisture, but the soil must never become waterlogged. Deep watering is preferred, ensuring the root zone is saturated, and then allowing the top layer of soil to dry slightly before the next application.
The Devil’s Tongue Plant is a heavy feeder, necessitating regular fertilization to support the rapid growth of its large leaf and the expansion of the corm. Apply a balanced liquid fertilizer (e.g., 10-10-10 N-P-K ratio) every four to six weeks during the peak growing season. Some growers recommend a higher-phosphate fertilizer (e.g., 15-30-15 ratio) to encourage healthy corm development.
As the plant matures, the single leaf stalk can reach heights of four to six feet. If grown indoors, occasionally wipe dust from the leaf stalk and leaflets to maintain efficient photosynthesis. If situated outdoors, protect the large foliage from strong winds that could cause damage.
Handling the Dormancy Period
The life cycle includes a mandatory dormancy period, signaled by the natural senescence of the foliage in late summer or early fall. When the leaf begins yellowing, gradually reduce and then stop watering completely. Allow the leaf to turn completely brown before cutting it back, as the plant withdraws energy from the foliage back into the corm during this time.
Once the foliage dies back, the corm enters its resting phase and must be kept dry to prevent rot. If the climate has consistently mild winter temperatures and well-draining soil, the corm may be left in the ground. In regions with cold or wet winters, the corm must be lifted from the soil for storage.
To store the corm, carefully remove it from the pot or ground, brush off excess soil, and allow it to air-dry for a day or two. Place the corm in a container filled with a dry medium, such as peat moss, sawdust, or vermiculite, to maintain a dry environment. The ideal storage location is cool, dark, and dry, with a consistent temperature range of 40°F to 50°F. Inspect the corm periodically to ensure it is not developing rot or shriveling.
Encouraging Flowers and Propagation
The plant produces its unique, malodorous flower only once the corm reaches a sufficient size, typically after three to four years of consistent growth. This mature corm, often the size of a grapefruit or larger, initiates flowering in late winter or early spring, before the new leaf emerges. The flower, known as an inflorescence, consists of a spathe (a large, ruffled, maroon bract) surrounding a central spadix (a pale green to purple spike).
The flowering event is brief, lasting only a few days, and emits an odor resembling rotting flesh to attract its natural pollinators. After the flower fades, a new leaf emerges, and the annual growth cycle begins again. If the corm is not mature enough to flower, it proceeds directly to producing its single leaf.
Propagation is achieved by separating the small offsets, or cormlets, that form around the main corm. Detach these cormlets from the parent corm during the dormancy period (either in late fall when lifting the corm or in the spring before replanting). Plant the separated cormlets individually in containers; it will take several seasons for these smaller corms to reach flowering maturity.