I sowed sorrel in the spring of 2008 without any preparation of the seed (stratification etc.). I got several very nice clumps of sorrel a few weeks later. Two years ago I dug up, divided and transplanted some of the plants. It took them about a year to recover completely and return to the same productivity as they had on the previous site. Now they are all doing fine.
Common Weeds And Wild Edibles Of The World (HD video)