The guys from the Maine BJJ academy, just posted a very detailed video about the Pendulum (flower) sweep. As always, excellent material from them to improve your game.
The guard is a ground position where one combatant has his or her back on the ground, while holding the opponent using the legs. To change from the closed guard to a more dominant position, you generally sweep your opponent.
To sweep from the closed guard, you have the following options:
Standing Sweep from closed Guard (when your opponent tries to stand):