ShadowWalker,
Replant failure is a well known phenomenon with ginseng -not just cultivated roots. I've experienced it with woodsgrown roots also. I never fertilize woodsgrown stuff, but even after having grown for only a year or two, and leaving a dug out bed (rootlets were sold for transplant) for over five years, I planted maybe 1/2 pound and had only 3 or 4 seedlings show up the next spring. What seems odd is that the beds I chose to test this were beds where I had little or no disease and excellent growth and healthy plants. I've tried it a number of times with the same results.
There are some studies which postulate theories, but nothing definitive. So, at this point, no one really knows why this happens.