As I was weeding my front bed with some Black Magic Elephant Ears in it I noticed one clump was sending out runners, coming from the center of the clump! I have never seen this before when growing them in pots .. this was the first year I had put one in the ground. Is this normal?
Will these surface runners create bulbs? Is there a special name for these structures? Do all colocasia do this?
Colocasia are Stoloniferous plants, they send runners out which will make more tubers or bulbs, make sure you let them root prior to cutting them off :) It's kinda like offsets, you can't break them off too early!
Stoloniferous is where plants make Stolons (enlongated stems) and they create new plants, some Hippeastrum (amaryllis) and others in the Amaryllid family do this, hosta's are stoloniferous as or many other bulbs or epiphytic plants!
Josh
Thanks! Learned something new today.
X
Here is a bit of an expansion on Josh' explanation as it applies to aroids:
Colocasia grow from an underground stem known as a tuber. A stem is the plant's main support, base or central axis and its roots anchor the plant either to the ground, a tree or to a rock. A stem may also be a rhizome as well as a tuber (often incorrectly called a corm or a bulb) and grow beneath the soil. A stem may even spread as a repent rhizome creeping across the soil (repent indicates the rhizome runs roughly horizontally). A rhizome is just a stem (central support) that runs either along or just beneath the surface of the soil as can be seen with Ginger plants or with an Iris.
A bulb is an underground storage structure used to store starches and water that is only a condensed stem since it is the central support of the plant. A bulb normally has a basal plate and layers of fleshy storage leaves surrounding the bud that will form the next plant. The modified leaves are arranged in layers that are used for food storage. The perfect example of a bulb is an onion, just slice one open and you can easily see the modified leaf layers. The term bulb is used mostly in horticulture but never applies scientifically according to Dr. Tom Croat of the Missouri Botanical Garden to any aroid including Colocasia or Amorphophallus species. Tom is considered the world's top aroid botanist.
A corm is also an underground storage stem to which the above-ground parts may die back in the dormant season but is also not applicable (according to Dr. Croat) to aroids.
A corm often stores starch and when the corm re-grows foliage the new growth will come from the top with the roots growing from the base. Bananas grow from corms as do Gladiolas but the term corm is not scientifically appropriate for an aroid On Aroid l we had an extensive discussion regarding this subject just a few months ago and according to more than a few top aroid botanists the term corm cannot be used correctly for any aroid. By they way, there are many aroids that do not grow from a tuber either. Tubers are a unique for of stem. There are a select number of aroid species that have a corm-like tuber but the majority of scientists agree the term does not apply in the family Araceae (aroids).
A tuber is a strongly condensed stem as well as an underground structure which is almost entirely a starch storage organ. The buds for future growth and the roots all develop at the apex or top. The tuber can sometimes form as the tip of a stolen or runner as was described by Josh.
Stolons are stem runners or stem shoots that run atop or just beneath the surface of the soil's surface to produce new plants. According to scientist Christopher Rogers, "In Amorphophallus, Arum and Tymponium for example, the stem tissue is all encased the the small bud at the top of the tuber. That bud grows up wards into a leaf or two and outward into roots with the tuber beneath."
A potato is the perfect example of a tuber.
For a more detailed explanation including charts visit The University of Illinois Extension. If you look at the drawings you will see the differences. http://urbanext.illinois.edu/bulbs/bulbbasics.cfm
This message was edited Aug 10, 2010 7:40 PM
Alistair, if you are around feel free to clarify any of this.
Since I am aware that many growers do not like technical explanations or definitions I only made this response since it was requested. If anyone prefers to call a tuber a corm or a bulb then no other grower has the right to tell them they cannot do that. I only point out the scientific differences for those that like to know the what defines each form. There are commonly accepted usages in horticultural terms and in botanical science some of those applied to aroids by serious growers and scientists may be useful to some of us.
From Josh' excellent answer it was obvious there are those that do want to understand more detailed discussions.
Steve
You can throw the runners in a vase of water and they will root and send up leaves.
Thanks Steve for the detailed explanation. I've always had trouble differentiating tuber from rhizome. I've always associated corms with glads, but am amazed to find that corms are produced by bananas! I also thought that stems were always above ground too.
Very informative .. and I always like to learn something new.
Thanks again!
Anne
Thanks Anne. I am a curious creature and just like to dig for correct answers. I would never expect every grower to use all the terms correctly but I am also always in hopes some want to know the differences.
And yep, stems grow both above, below and across the ground's surface.
Steve
Excelent... thanks
X, do yourself a favor and get those babies in a pot quickly or you will never rid yourself of them. I know they are a nice problem to have but they know no boundries.
Lol .. I've already discovered that .. they are trying to mug my curcuma.
Now I understand what is happening to mine. I have one in a pot and it sent out runners all around the pot and I have new leaves sprouting up all around the pot. This has never happened with any of my other ones, and I was shocked to see these. I too thought I was losing it. This is my first year with this one, it was a gift from a friend. Now I have many babies sprouted around the pot in the yard.
