I've never heard of Tetrapanax being poisonous. I'm not sure about the fruit, which it might produce in your climate--if it's a concern, you can just keep the flowers clipped off. On the other hand, the leaves (especially the new ones) are covered with a powdery substance that can cause allergic reactions in some people if inhaled.

Thank you, Johnnie,
I went to Cornell U's poison plant page, and didn't see it listed. The powder on the new leaves won't be a bother. It will be planted away from frequent traffic. Thanks!

Taffy, make sure that you plant it where it can't escape or you will have a ricepaper plant forest in no time at all.

Thanks for the advice, Nigella. I plan on sinking a metal garbage can into the ground, and leaving the rim sticking out about an inch. The bottom would be cut out of the garbage can for drainage and access to water. Do you think this would suffice for containment? I want just one large specimen plant out in the landscape, not a forest.

Actually, I've found a source for the variety 'steroidal giant' which won't die back in my climate, and should get about 25 feet tall. I'm quite excited about it. Will just underground containment work, or should I keep the flowers snipped off the plant, too? Thanks for any info!