Which Came First - Flowers or Bees?

Youtube Channel It's Okay To Be Smart goes into one of the bigger questions in the universe: which came first, flowers or bees? Bees and flowers have an amazingly close relationship. Flowers need bees in order to reproduce, and bees need flowers to feed their colonies. Take away one, and the other would disappear too. It begs the question: When it comes to evolution, which came first, the bees or the flowers?