The uprights Alocasia macrorrhiza are hardy for me in zone 7. It does die down in the winter so it has to start over each spring and never reaches the size of the ones I keep in pots and take in. I did notice it did not come back this year. So it seems to be shorted lived outside for me.
Since you are in a warmer zone and have a protected spot you may get bigger growth.
I don't know about planting it side ways.
But yes they are related to colocasia and xantosomas.
I have one with a taller truck than these two. These are last years pictures. I need to update.
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Broomhildah, they are "root hardy" here in Birmingham. I always cut them down, fill a large black, plastic flower pot with chopped leaves and cap it upside down over the stumps for protection. Here it always comes back. I remove the pot of leaves around April 1. If frost threatens, I cover it with a flower pot. Next year, when frost time comes, just break off a few of the side shoots that come off the old trunk and plant them for plants to share with friends. If you plant your large one now, it will have time to become established before winter. Now, about the top. Cut it off near the ground after planting. The stump will put out new plants all around itself. Cut remaining stump to an appropriate length and stick it down into a large pot, maybe a 5 gallon bucket with drain holes. Place it in the shade. You will never know by looking that it was ever removed from the mother plant. It will root and you have another plant. If you have leftover stump pieces, I would stick them in a pot of soil and I believe they may root as well. Feel free to email me if you have more questions.

It is hardy for me in Oklahoma City (7a) in the ground. I just throw a bag of mulch or soil over it for the winter. When I take it off in spring, the leaves from last year are all mushy. I just trim this off (I even accidentally pulled off the top of the bulb, but it still came back), and once it gets warm enough here, it begins to put up foliage.

Susan

Thank you for your information. I love the pictures. Yours are waaaayyyyy more beautiful than mine! I guess mine have been kept in the cave for too many years. I'm going to follow your advice and plant them this weekend. Hopefully they will look healthy by next summer.

Christy

I have to plant in the ground. Having had back surgery and cervical problems, there is no way I could haul those pots up the steps and into the house, not to mention the room they take.

Generally speaking, I'm not much of a "risk taker", but I find an outlet for adventure in zone pushing.

TSmith - are you kidding me? Actually cut the tops off the bulbs? How much? I know when I pulled on my A. macrorrhiza this spring, the top popped off, and I thought I killed it for sure. But several sprouts in about an 18" diameter, are up now, whereas last year, it was just one. Is that kind of what you mean?

I like the idea of putting pots over the top. But, if you're using black plastic, which are pretty light weight, I'm assuming you're putting something on top or around the sides to hold them in place????? OKC is the 3rd windiest city in the nation, so no way would the pots stay in place for longer than a day.

You have some great ideas! THanks for sharing.

Susan