Hey guys i have seen the stem which holds the seeds reach 10 plus feet. It is plentiful around here and this summer i have been making good money from it. While out scouting for ginseng its a good way to make some extra cash. I made 300 last week alone just on cohosh.
cohosh will be around waste tall if its huge and the seed stem it can be 7 or 8 feet but its a good money maker if you will work it like a job 100 bucks a day can be gotten. You also almost always find ginseng while digging it. I dig everyday for cohash and have found some serious ginseng spots while doing it good luck to you.
Here in West Virginia, the really big ones (giants\") have the top foilage spread at around chest high, with the seed spike reaching up around 7 feet. ... In a nice big patch of matures the average nice plants run at a foot to 2 feet shorter than the \"giants\".