The fact that they are all on commission is your first indication of trouble. No training, but they'll still try to tell you they know what they are talking about even when it is dead wrong! If you told them you wanted to plant a tree at the bottom of your filled swimming pool they would tell "sure, you can do that". Whatever they need to tell you to get your business.
Thankfully, there are many other REAL nurseries run by folks who care & have a clue of what they are talking about. MVN seems OK at first until the $2k you just spent on landscaping dies 1 year later.