Amorphophallus konjac is an herbaceous perennial native to the forest margins of East Asia, sought after for its distinctive, umbrella-like foliage and unusual bloom. The ‘Leo Song’ cultivar is a desirable variation of the species. This guide focuses on the specific details and care requirements necessary for the successful cultivation of this particular plant.
Identifying the ‘Leo Song’ Cultivar
The ‘Leo Song’ cultivar is distinguished from the standard A. konjac by the unique coloration and pattern of its petiole, the fleshy stalk supporting the single, massive leaf. While the species typically displays a pale pink petiole mottled with olive-green splotches, ‘Leo Song’ exhibits a striking variation. Its stalks are a fleshy tan or creamy ivory color, accented with tiny black flecks or highlights of pink, creating a visually distinct appearance that collectors prize. This coloration provides a lighter, more contrasted look than the generally darker, mottled patterning of the wild type. When a mature corm of ‘Leo Song’ produces a bloom, the glossy purple inflorescence—consisting of a spathe and spadix—is generally identical in color and structure to that of the species.
The Unique Annual Life Cycle
Amorphophallus konjac is defined by a distinct annual rhythm, transitioning between a vegetative phase and a dormant period. The plant grows from a corm, a large, underground storage structure that holds the energy necessary to produce the year’s growth. In the spring, the corm sprouts a single, highly divided leaf on a thick petiole, which expands to create an intricate, umbrella-like canopy that can reach several feet in height and width.
During the active growing season, this single leaf performs the necessary photosynthesis to store energy in a new corm, which forms on top of the old one and continually increases in size. As temperatures cool in the late summer or fall, the foliage naturally senesces, or dies back, signaling the start of winter dormancy. The mature corm then rests, storing its energy until the following spring.
If the corm reaches a sufficient size, typically after three to four years of growth, it will produce a bloom instead of a leaf when it emerges from dormancy. This inflorescence, often called the “corpse flower,” consists of a spadix surrounded by a dark maroon to purple-brown spathe. The flower uses the corm’s stored energy to heat up and emit a powerful odor of decaying flesh, which attracts its specific pollinators, carrion flies and midges. Once the bloom cycle is complete, the plant will then produce its single leaf for the season to restart the cycle of energy storage.
Specific Cultivation Requirements
Successful growth of the ‘Leo Song’ cultivar requires attention to conditions that mimic its native subtropical forest environment. The plant thrives in a location that receives bright, indirect light or dappled shade, as direct, hot afternoon sun can easily scorch the foliage. During the growing season, a temperature range between 68 and 77 degrees Fahrenheit is optimal for vigorous development.
The planting medium should be a fertile, humus-rich soil that is also highly porous and well-draining, as the corm is susceptible to rot in waterlogged conditions. When the leaf is actively growing, the plant requires consistent moisture, and it is beneficial to fertilize regularly with a balanced product to support the rapid growth and corm development. The corm should be planted at a depth roughly twice its height to ensure stability and proper root development.
Once the foliage begins to yellow and die back in the fall, watering must be reduced immediately and eventually stopped entirely as the plant enters dormancy. Although the corms of A. konjac are hardy in the ground in climates as cold as USDA Zone 6, in colder or very wet regions, it is safer to lift and store them. Store dormant corms in a cool, dark, and dry location, such as in dry peat moss, with temperatures maintained around 40 to 50 degrees Fahrenheit until the following spring.
Propagating New Plants from Corms
Enthusiasts typically increase their stock of ‘Leo Song’ by separating the offsets, often called cormels or “pups,” which the parent plant produces annually. The A. konjac species is known to be a prolific multiplier, and the ‘Leo Song’ cultivar is noted for making a tighter clump by keeping its offsets close to the original tuber. These small, new corms can be harvested when the parent plant is fully dormant, usually in late autumn or just before new growth begins in the spring.
To prepare the offsets for planting, they are gently detached from the main corm, and any cuts should be allowed to callous over for a few days to prevent fungal infection. The cormels can then be planted individually in small pots filled with a well-draining medium. Providing warmth and avoiding excessive moisture initially will encourage the new corms to establish roots and eventually sprout their own miniature leaf in the first growing season.