I am guessing that they are so tropical and maybe extremely picky that they can't be grown out of their environments... not sure... that's a guess.

okay I found it at Native Habitat Ethnobotanicals... for $30. There's a few things about NHE. They take FOREVER... and you never know when they will ship. Plus, there are no instructions on how to grow. With the tropical Piper family, I'd think it'd need high heat, lots of water and probably shade during hottest part of the day... although you don't have your zone down...I am assuming that you aren't in a tropical zone.
If you have a greenhouse, you will probably have no trouble growing one.

You are awesome. And apparently I am not. Thanks for all the info. I do have a greenhouse and am excited about kava. I'll keep you informed on the progress.

why aren't you awesome? You have a greenhouse... pretty awesome to me! Now... would you take a cutting of it and share it with poor little me? :oD Lee at Native Habitat is a very nice man, but very very slow... I ordered a plant in February...still haven't got it.. he grows it from cuttings then sends it. I have gotten many plants from him, if you are willing to wait 6 months, you will get good plants, but you kinda have to guess on how to grow it... I have a few medicinals from Mexico that are still alive.... :oD

I remember traveling from the Midwestern US (where I had a fairly deep tan) to Hawaii, and I got a severe sunburn very quickly the first day - the intensity of the light is much higher compared to 37 degrees latitude!! I'm guessing that the plants that are happy with some shade in Hawaii would probably want full sun in much of the continental US.