The Amorphophallus Konjac is a perennial cormous plant originating from the warm subtropical and tropical regions of Eastern Asia. Known by several common names, including Konjac, Voodoo Lily, and Devil’s Tongue, it is cultivated both for its large, starchy corm, which is used in food production, and its unusual ornamental features. The plant’s annual growth cycle is marked by a massive, underground corm that produces a single, intricate leaf structure. This single leaf, which can reach up to four feet across and six feet tall, unfurls on a fleshy, mottled stem, creating an umbrella-like canopy. In mature specimens, a large, malodorous flower, which smells distinctly of rotting flesh to attract pollinating carrion flies, may emerge before the leaf in the spring.
Essential Environmental Needs
The foundation for successfully growing Amorphophallus Konjac begins with selecting the correct growing medium and placement. This plant requires a porous, well-draining soil mix that is rich in organic matter. A blend of standard potting soil amended with materials like perlite, compost, or humus provides the necessary fertility while preventing the dense compaction that can lead to corm rot. Since the plant’s roots grow from the top of the corm, the planting depth should be approximately twice the height of the corm itself to ensure stability.
Proper light exposure is best provided through bright, indirect light or dappled shade, which mimics its native understory habitat. While it can tolerate some full sun, particularly in cooler climates, intense afternoon sun can easily scorch the large, delicate leaf blade.
As a tropical species, A. Konjac thrives in warm conditions, preferring temperatures between 68 and 77 degrees Fahrenheit during the active growing season. The plant is cold-sensitive, with the foliage and inflorescence being intolerant of frost. Outside of tropical or subtropical environments, where the ground does not freeze, the corm must be lifted and stored for the winter. Even in its native range, the plant requires a dry, dormant rest period each year.
Managing Active Growth
The focus shifts to consistent care throughout the growing season, which usually extends from late spring through early fall. The plant is a heavy feeder, and its rapid growth cycle requires regular nutrient supplementation to support the massive single leaf. During this phase, a liquid fertilizer applied bi-weekly is recommended to ensure the plant has access to nutrients.
A balanced fertilizer, such as a 10-10-10 NPK ratio, is often used, but a higher-nitrogen formula is suggested during the initial leaf development for foliage growth. Once the leaf has fully expanded, reducing the nitrogen and providing a fertilizer with higher phosphate may help stimulate the development of a larger, healthier storage corm for the following year. Fertilization should be suspended completely as soon as the leaf begins to show signs of yellowing in the late summer or fall.
Watering must be frequent and generous throughout the active growth period, keeping the soil consistently moist but never waterlogged. Due to the plant’s tropical origin and high water demand, it can even tolerate standing in shallow water during the peak of summer, though this is not necessary if the soil moisture is maintained. High humidity is appreciated, and container-grown plants benefit from regular misting or placement near a humidifier. While resistant to major pests, dry environments can lead to infestations of spider mites, which can be managed with simple organic controls like insecticidal soap.
Preparing for Dormancy and Storage
The transition into dormancy begins when the temperatures start to drop and the days shorten in the fall. The visual cue that signals the end of the growing cycle is the single leaf turning yellow, collapsing, and dying back completely. It is important to allow the leaf to fully brown before removing it, as this process allows the plant to draw all remaining energy back into the corm for winter storage.
As soon as the leaf begins to senesce, all watering must cease immediately, and the growing medium should be allowed to dry out completely. If the plant is in a container, tipping the pot onto its side helps ensure thorough drying and prevents the onset of rot. The corm should be lifted from the soil before the first hard frost if it is grown in a climate where the ground freezes.
To prepare the corm for storage, it must be cured by allowing the exterior to dry for several days in a cool, well-ventilated area. After curing, the corm should be stored in a cool, dark, and dry location that maintains a temperature between 40 and 50 degrees Fahrenheit, such as a cool basement or garage. Storing the corm buried in dry peat moss, vermiculite, or in a paper bag prevents dehydration while minimizing the risk of fungal issues. Regular inspection throughout the winter is necessary to monitor for any signs of mold, rot, or excessive shriveling from dehydration.