Where are you located? I'm in south-central Kentucky now and grew up in Arkansas (zones 6 and 7, respectively) and sassafras
volunteer everywhere here. Basically if there is another tree that I don't mow/graze close
enough to, a sassafras tree will emerge there. Evidently they
really like nurse
trees.
If you live anywhere in the southeastern US, you can probably find them pretty easily. They have several different leaf shapes, often on the same plant, so take your time with the identification. Sometimes they look a little like young wild mulberries here.
You're welcome to come to my place and I'll point some out. You're welcome to all that you are willing to dig up.
Regards,
Geoff