transplanting shrubs, bushes and flowers

[John Owsley]

I live in Louisiana and run across old homesites and random shrubs, trees and flowers growing in the middle of nowhere. I would love to dig up these plants, trees, shrubs and flowers to enhance my property and save some money. My issues are the not knowing how or when should I do this. I do not want to destroy the plants, so that's why I'm looking for some advice. Thank you.
John