After reading many bad accounts of Sweet Flag I would like to share
the information I have gathered from a wide variety of sketchy sources.

Acorus Calamus, aka "Sweet Flag"

The rumor persists that this is an interesting plant, and it is. 
It however doesn't bless everyone with it's interesting properties.
It is distantly related to cattails, and the root is what most 
people are refering too. It is easily grown from Texas to Canada.
It just seems to have problems adjusting the first year. It is
highly frost tolerant going into dormancy during the winter. Personal
experience it seems best when harvested around the summer soltice.
It require a lot of water and cannot be overwatered. It really likes
rich soil, but will grow in poor soil (albeit poorly). The roots
can be broken into about 2 inch sections and replanted giving one
many many more calamus plants the next year. 

First off there are two strains, with greatly different effects.
One of these strains has been determined to be carcinogenic and
the other has not been assayed. Most of the literature refers
to the carcinogenic strain which originally comes from Asia. 
There is also a strain which is indigenous to America which was
held to be sacred by the Native Americans. It was used in 
religous rituals, rumor has it, that it helps see into the spirit
world. It was also taboo to sell the root, it could only be
freely given as a gift or the root wouldn't bestow it's properties.

If you are interested in trying some Sweet Flag, first get
a good source of it, not the Asian strain either. The most preferable
source is straight from the ground, with a clean water source nearby.
It requires lots of water and would probably soak up anything nasty from
the local water table, so beware. The second choice is some dried from a
reputable source. Avoid any that is bought through a local herb store or
food coop, they sell it for pot pourii and it isn't dried properly for
consumption.  There have been numerous reports of people eating some from
these sources and vomiting. The root itself has an opposite effect, so 
bacteria must be growing on the improperly prepared root. Sweet Flag
that I have seen from these sources, isn't even completely dried
and doesn't smell like it should, so please be careful of your
source. A recommended source is JLF. Also a dried root is nowhere near
as potent as a freshly picked one, the effects are not as pronounced.

AAAAGHHHH! The taste is horrible! Usually it helps to nibble away at the
root chewing each bite (if it's swallowed whole it won't digest and 
nothing will happen). Wash it down with something, experimentation
with different beverages will tell what works best for you. Some
prefer sprite, some prefer milk, some prefer fruit juice and some
prefer coke. For best effects try to eat about 12 inches of the root.
Also over time the root will actually start to taste sweet, but that
comes after eating it several times. Avoid alcoholic beverages, because
they will counter it's effects. It does go quite well with various
types of smokeables however. It takes about 2-4 hours before anything
starts happening and it is very subtle. In fact so subtle that if
your at a loud party, you won't notice a thing. It's best to be
out hiking in a quiet wooded location. Then it may or may not do
anything depending on many factors which are unknown. However
the experience can be quite incredible at times. It seems to work
best when one sits perfectly still and observes nature in it's
beauty. If you're lucky mother nature will reveal one of her many
secrets to you. If you're looking for a cheap legal buzz, something
to party with, then calamus is not for you. Calamus takes time, 
and effort with very subtle results. It also may not do anything for
you the first time or the second time or possibly ever. It doesn't
work for everyone, and for those it does it is fickle. 

Walt Wiltman wrote a book called _Leaves of Grass_ which makes numerous
references to Sweet Flag and has a very good description of its
effects hidden in the poetry. It can leave you with a greater 
reverence for nature.