Mine easily take up a 3x3 space if not more.

Here is a link that might be useful: The Corner Yard

Agreeing, more if they are happy, as in full sun with good soil. Altho if you put 2 about 6in. apart, you can squeeze them in a 4x4.

I also agree, 3'x 3' minimum. I moved mine out of the raised beds this year so they can have their own space.

Here is a link that might be useful: Tales of a Transplanted Gardener

Me three. I moved mine into containers because they take up too much space.

Dan

I did mine in containers last year and the stems of the lower leaves kept bending and breaking over the sides of the container. I think it was either a 16 or 18 inch one. This year in the SFG it's been doing much better even though it got blown over by a ridiculous storm last night.