I have dug a lot of sang and planted a lot of the berries when I was a teenager living in the hollers of southern WV. It does not take 15-20 years to get to harvest size, probably more like 5-6 years to get to be a decent size 3 or 4 prong not huge but decent harvest size. I have a few hear at the house that I transplanted a couple years ago along with some small ones from the berries off those. If you have never hunted any sang it is not easy to find when you start out. There are a lot of things in the woods that look kinda like it but not quite. But after a couple years it will get a lot easier to spot without having to walk right up on it.