Plant of the Week
Those of us involved in extension work are often asked to identify plants. Usually,
it’s to satisfy nagging curiosity, but occasionally it takes on more significance
as when a child has eaten an unknown plant or the police need to identify plant fragments
found clinging to the clothes of a murder suspect.
Latin: Amorphophallus konjac
This week's sample of interest was of the curious variety, and it's easy to understand why a blooming specimen of Devil's tongue would arouse such curiosity.
Devil's tongue (Amorphophallus knojac) is a member of the philodendron (arum) family. The calla lily flower can be thought of as basic model for the family with a leaflike spathe surrounding a protruding column of tiny individual flowers called the spadix.
But in nature's grand measure of diversity, these flowers may be tiny or mammoth, which is the case with devil's tongue. The plant, from southeast Asia, produces a large tuber which can weigh 22 pounds and be as much as a foot across.
From mature tubers, a single flower stalk arises which can reach at least 5 feet high. The showy pink spathe unwraps from this stem like an upside down designer mini-skirt with a generous split up the side. The largest flower in the world belongs to an Indonesian relative, the titan arum (A. titanum), which produces a bloom as much as 12 feet tall.
From the center of the mini-skirt extends a giant burgundy to brown spathe, which may be as much as 2 feet long and as thick as your arm. In nature, the plants have evolved to be pollinated by flies, so, to attract the pollinators, it mimics the scent of dead water buffalo.
The foliage of Devil's tongue is equally unique. After flowering, a single leaf forms, which can grow as tall as 4 feet and spread out in the fashion of an umbrella frame to look like a giant dissected mayapple leaf. The leaf petiole is often marked with patches of dark green or brown giving rise to common names such as leopard arum or umbrella arum.
On researching Devil's tongue, I discovered it is one of two Amorphophallus that are cultivated for their edible tubers. The Chinese have grown it for over 2,000 years, and today it is a relatively important starch plant in Japan. It’s sold in blocks like tofu and is used in soups and stew-like dishes to provide a chewy texture.
Devil's tongue is not hardy out of doors and must be treated as a houseplant. A specialist with the International Arum Society informed me that A. konjac is becoming quite common in the plant trade but this is my first encounter with a blooming specimen. According to the discussion on the web, this is the easiest and most dependable flowering of the Amorphophallus species.
The family who owned the flowering specimen under discussion had been growing it as a houseplant for 10 years and were unaware that it bloomed. They treated it as a typical houseplant and grew their specimen in a 10-inch pot.
Progressively larger pots and routine fertilization during the growing season would speed the growth of the tuber and hasten flowering. The plant can be over-summered out of doors in the shade but must be protected from freezing in the winter when the tuber goes dormant and dies to the ground.
By: Gerald Klingaman, retired
Extension Horticulturist - Ornamentals
Extension News - April 5, 2002
The University of Arkansas Division of Agriculture does not maintain lists of retail outlets where these plants can be purchased. Please check your local nursery or other retail outlets to ask about the availability of these plants for your growing area.