Re: Adding legal herbs to shisha?
The term native American is used to denote the notion that the Amerindians are somehow more "native" then others. They use the term a long with PC Whites to advance an agenda of victimhood and cultural warfare. If you haven't noted as much you need to pay more attention to what a term actually implies, why it's used and why would someone use rather then identify one's self in a way that actually has some ethnographic meaning.
The fact that other words are used improperly to advance an an ethnic/political agenda doesn't make it any more legitimate.
As to what the various Amerindian tribes smoked other then tobacco i'd say the matter is exceedingly obscure for the simple reason that written evidence is non-existent prior to European colonization and very scarce since that time. The archelogical record is sporatic at best meaning that we simply don't know what smoking mixtures were popular with which tribes to what extent prior colonization. We do know that some of the mixtures in question were highly dangerious and often they were psycotropic.