4runner...
Here in middle tn... it is very common for the seng to grow mostly on the bottom 1/4 of a hill.
The higher you go up the hill (to a point - generally) the less companion plants, and less undergrowth in general.
Some exceptions to that... hillsides with deep hollows, high ridges and that hillside faces back near due north. In cases like that companion plants and seng will both show up higher on the hill... some times even up near the top of the ridge.
In middle TN, we do not have mountains, just hills and hollows. In my county the highest elevation is around 1100 ft... and lowest around 600.
I find the majority of the seng below 750'.
Exceptions would be those high hillsides, deep hollows where you have a direct north facing hillside, or where you have a side hollow running up on a hill like that. In those type locations you may find it up around 800 or even 850'.
This may be one of those north/south things too... the more south you go, it just gets hotter, and the sun is just hotter, and drys out the ground more.
The kind of limitations I see to where seng grows in my county, may not apply to someone over in the east TN mountains at all, or to someone that lives in a more northern state. I hear that up in Main that you find seng on south and west hillsides... and that just does not happen around here. About the only thing that grows on our south and west hillsides are oak trees and saw briars.
Also... if you have any river or creek bluffs, or just steep rocky hillsides that face north to east in your area I often find the best seng growing near the bottom to about 1/3 way up on those bluffs. It is hard hunting, because of how steep it is and how rocky (footing often gives way)... but if you can get up on the bluff some, to where there are flats here and there and check those... man I find some really good seng in places like that.
Go where few (if any) men have ever made the effort to go and you have a good chance of finding better ginseng.
TNhunter