amorphstory

The Story of my Variegated Amorphophallus konjac 'Shattered Glass'

One day I noticed that one of the small side corms taken from a large pot-grown konjac generated a leaf with a small sector of variegation. The sector persisted each year. It encompassed about one third of the leaf circumference. I marked that side of the pot so that eventually I could collect young corms derived from the area where that sector occurred. Eventually, I recovered a small plant that had variegation dappled through all regions of the leaf. The second year I grew it in a sunny spot and the white regions burned badly. Since then I have grown it where it gets full sun before noon and dappled shade for the rest of the day (Massachusetts). It does just fine. A picture of it taken in July 2000 is here. This plant produced a leaf 2 feet in diameter in its 3rd year. The variegation is unusual. Some regions are nearly white with green flecking. In other leaves a beautiful silver white edge pattern sometimes appears. When a large white area is formed it is associated with pink breaks in olive portions of the petiole color as seen in this petiole and in this petiole.

Some corms generated from the parent plant produce leaves that are nearly white . They do not produce enough carbohydrates to generate a new corm and eventually die, although they are a conversation piece while they last. I keep some pure white ones on my steps and they live for almost the entire summer. Others have some green but may be too weak to grow a big corm. Some are unevenly variegated and may eventually produce good offspring but time will tell. The good news is that I now have some with very promising variegation distributed throughout the leaf (this one for example). Although the variegation pattern is somewhat different each year from each corm, once the variegation exists throughout the leaf it has remained that way in the following years with only two exceptions where plants eventually went all green.

In 2004 my oldest 'Shattered Glass' flowered. Since the spathe contains both chlorophyll and anthocyanin (reddish purple) and the mutation causes chlorophyll variegation, I was not surprised to see that the spathe was mottled dark and light (see image). This year the same corm leafed out from the side of the petiole scar and I felt great when it maintained its wonderful variegation even after flowerin.

The behavior of this plant suggests that it is a genetic mosaic. The fact that I get some all white and all green offspring from mosaic plants rules out an infectious virus as the cause of variegation. Hopefully some day a stable white-edged form will arise but until then the mosaic pattern is still very exciting. Each spring I check them regularly to watch the blotch patterns appear as the leaf unfolds.

Offspring are very variable and I'd estimate that only one in 40 are uniformly variegated. I sell only the finest offspring so that you don't have to wait years like I did to get a good one.

It is probably one of the rarest of all Amorphophallus, even less common than A. titanum! The cultivar name for my new mutant is 'Shattered Glass'.

Below is my summary of this species, its mutations, and the care of the plant.

Amorphophallus konjac K. Koch (synonym: A. rivieri Durieu ex Carreirre)

Amorphophallus konjac is native to Vietnam and southern and southeastern China and is found either in small fields or near the edges of the forest. Corms of this species can attain 15-20 lbs after several years. A corm this size produces a leaf about 5 feet wide on a petiole of about 3 to 3 ½ feet tall. Most strains of konjac have marbled petioles of pinkish gray with olive blotching. The leaf is radially symmetrical and highly dissected, glossy on top, and very attractive. The petiole base can attain the diameter of a human forearm. To attain such size can take up to 7 years and is dependent on proper culture over several years. Corms above "grapefruit" size may send up an inflorescence. The inflorescence is a huge shiny spathe that precedes the leaf in the spring and will stall the emergence of the leaf by a month or two. The spathe is burgundy or maroon with some blotching and like many species in this genus smells like rotting meat as beetles favoring such delights pollinate it. The spadix exudes globs of smelly droplets. Under good growing conditions the corm will significantly increase in size each year. As for the life cycle, the existing corm shrinks away as the leaf unfurls and during the growing season a new corm replaces it. This is when the increase in size can occur.

Plants should be kept in partial shade although they will tolerate full shade and even full sun depending on temperature. In warm climates, direct planting in the garden can be done even if the winters are too cold to leave the corm out. Simply dig up the corm with the leaf and let it dry out for storage. In cold climates it is possible to plant directly in the garden but emergence will be late and the growing season short. The pot cultivation of this species is as follows. Dry corm with "pink" growing tips are planted in a soil-free highly organic peat-based commercial medium. The corm is planted just below the surface. I like using the squat type "azalea" pots because of their low profile and the plants top heavy nature. The size of the pot depends on the size of the corm. For corms the size of "dimes" use 3-inch dia pots, for those the size of "quarters" use 5-inch pots. "Basketball" size 20 pound corm goes in a large palm pot that is probably 50 gallons.

This species is a heavy feeder. Use constant dilute liquid feed (Peters 20-20-20) or the highest recommended rate of Osmocote 14-14-14 time release fertilizer. The size of the leaf appears to be dependent, not on the conditions of the present season's growth, but on the past season's growth. The bigger the corm, the bigger the leaf for that season. In order to maximize growth of the corm from year to year try to keep the leaf alive as long as possible, although the corm does need a dry dormant period in its life cycle. Warmth will initiate growth. To avoid the risk of rotting, take the dormant corm out of dry storage in the spring and leave it unpotted in a warm room. When the pink 'eye' is starting to pop out of the top of the corm, the corm is planted. In the fall with the risk of frost (e.g. if growing in Zone 5) the pots are knock over so they will not get any rain and the pot will dry. Alternatively, it could be placed in a greenhouse or a patio and allowed to dry. The leaf will die back. Do not cut it off until it completely yellows and collapses as is may be translocating sugars into the corm until it is withered. Once it is dry, it can be stored in the dry growing medium until spring and then dug up so that small corms can be separated from the mother corm. Winter storage can also be in dry peat or in the open air. Storage temperatures should be somewhere between 42 and 50F. If stored too warm, the corm may grow at a time when you are not prepared to grow it. Corms can be started in pots indoors in cold climates and then transferred outside when night temperatures do not drop below 55F. Remember, the warmer the temperature the faster the growth and the longer the season for the leaf. This species is fairly cold hardy and can survive in ground as far north as Raleigh, North Carolina if soil is well-drained.

Propagation is generally by offset. When the corm is dug unpotted in its dormant state, you may find small corms attached by stolon-like structures to the main corm. These can be separated and potted individually. Cultivars that are available (some very expensive and rare) include 'Leo Song Variant' with a pinker petiole, 'Gordon's Gold' with a yellow leaf especially in spring, 'Pinto' an extreme dwarf, 'Nightstick', with an eggplant colored petiole, and 'Shattered Glass' with white, silver and variegated leaves.