These are all beginner mistakes that most of us have made, Pamela.
Take my word for it, though. Not all people working at stores that sell plants know anything about growing them. Especially at places like HD, Lowe's and Wal-Mart the employees often don't know a thing about plants so unless you ask the nursery manager, you're not sure to get good advice there.
Go shopping at a real nursery - i.e. a place that ONLY sells plants - and you'll get good plants and good advice most of the time.
