My background
Let's get one thing straight: I don't know very much about growing taro, here in Hawai'i or anywhere else. All I can relate are my own personal experiences, limited as they are, some guesses based on those experiences, and some regurgitation of things I've read or heard.
If you live in Hawai'i and want to grow stuff, it makes a certain sense that you would grow some taro. Obviously it's a plant that does well here, the Hawaiians (the original indigenous people of Hawai'i) grew taro as a staple food. And it's used for a lot of different local foods (such as poi, lau lau). I've been told that the entire plant is edible, I've only eaten the corm (the "root") in the form of poi and as cubes in coconut milk, and the leaves and stems (called the "petiole") in my faux lau lau. Come to think of it, I don't really think there's much more to the plant...
In June 2006 my friends Andy and Joy gave me three complete plants, each with a corm about the size of my fist. On getting home, I immediately transplanted them into a container. And they proceeded to appear to die on me. As the leaves turned yellow, then brown, I cut the petioles off near the base. Eventually there were no leaves, and I had figured them to all be goners, but never got around to dumping them. A couple weeks later suddenly there were leaves coming out, and the plants made a complete comeback.
After a couple months I transplanted the whole bucket contents to a raised bed. It seemed pretty spiffy. The plants grew fabulously, and I was able to collect some leaves to make my first batch of faux lau lau, which was actually pretty good.
My close personal friend Mister Lars gave me some more taro plants in Fall of 2006, and I planted some of those in the first bed, and put a bunch more in the raised bed next to it.
In December 2006 I tried harvesting the corms from my first three plants. And was completely surprised, in a bad way. The base of the plants were quite large, leading me to think that the corms were very big. So dug 'em up, and there was practically no corm at all. Almost zero! Much less than the original plant had. I believe that the original corm got used up developing the new leaves.
So I cut the original three back into hulis, replanted them (incorrectly again, I'll explain that below) and they grew fine. Many new keikis have grown off the original plants, many of those I've cut off and transplanted and grown successfully into their own plants.
Starting out
There are two low-tech ways to start taro, either using a huli or an oha. The huli is a mature plant that has usually been harvested, the bottom part of the corm cut of for use, and the ends of the petioles cut off. An oha is actually an offshoot of the corm, basically another taro plant starting to grow out the side of the corm. There's also a high tech way of propagating taro, using tissue cultures and a lab and stuff. Sounds complicated, and beyond my means.The huli Taro is kind of cool in that it is "re-used." When the plant is harvested, the top half of the petioles are cut about half-way down, so that there are no leaves, and all but the top inch of the corm is removed. This is then planted, and grows the new corm, develops new leaves, and just sort of continues. I have no information as to how long this continue, so it's possible that the current taro plants could be pretty dang old if progated that way.The oha After a while a taro plant will start to have these little shoots, or mini-corms pop out on the sides of the main corm. These will develop petioles, grow out, and then produce leaves. These can either be cut off while leaving the main plant in place, or split off when the main plant is harvested. For me, once they get to having petioles that are 8 or so inches long, if I want more plants I then take a kitchen knife, cut down straight through into the dirt half-way between the main plant and the keiki, and slice through to seperate the keikis piece of form from the main plant. I then transplant the keiki into it's own place. This has been pretty successful for me so far. Planting One thing I learned from the book Taro: Mauka to Makai was how the corm grows: new corm material is added to the top of the corm. The bottom of the huli becomes the bottom of the corm. The corm only grows a couple inches above the growth media. If you plant the huli an inch in the dirt, you're going to get a corm about three inches tall. Plant the corm six inches down and the corm should grow to be about eight inches. So I'm looking forward harvesting and replanting my taro to see how well it does.
This image, from the book Taro: Mauka to Makai, explains a huge amount of information in a very small space:
Some taro related resources on the web:
Taro and Ti: a yahoogroups listserver for discussing taro, ti, and other tropical plants.
I have some more pictures plus personal gardening info on my blog at http://www.zone11.org/blog/agblog.html
Here is a picture of one of my taro beds as of mid-May, 2007:
Here is a picture of the top and bottom of a taro leaf:
And the base of the taro plant looks like, you can see some big oha have grown out of the main corm: