Kevin Kelly, founding editor of Wired magazine say's, "Make customers as smart as you are. No one is eager for a core dump, but if you can remember my trouser size, or suggest a movie that all my friends loved, or sort out my insurance needs, then you are making me smarter. The rule is simple: Whoever has the smartest customers wins."
In the horticulture and the nursery business, educating the customer is vital. Sure, there may be plenty of people who will shop with you and never learn something new. The "customer evangelist" is different. They enjoy learning new things and will spread the message that your the place to go to become a better gardener. It's what will separate you from the warehouse garden shops where price is the overriding concern.
Teach your customers how to become better gardeners, and you'll have customers for life.