Depending on who comes in and what they buy she knows the goings on around Ryden

When Avery buys white roses it's the anniversary of a death of someone close (dun dun dun)

If Daniel orders tiger lilies (when in season) then Jillian has a dance thing that day. He usually comes in first thing in the morning because he's learned that Margarita likes to spread the word about the recital/concert/whatever and get the thing more traffic

Every Sunday Avery gets 2 dozen carnations/roses to bring to the unmarked graves of veterans. And you thought he was just a heartless asshole but really he's just an emotionally traumatized kiddo who hides his pain behind asshole