Push the toothpick into the styrofoam ball where you want one stem of hydrangeas to go. Wiggle the toothpick around to make the hole a little larger.
Put hot glue into the hole and immediately stick the hydrangea stem into the hole. Hold it secure until the glue dries; hot glue only takes a minute to dry.
Continue making holes and glue the flowers into it until the entire styrofoam ball is covered in flowers.
Cut the ribbon double the length you want it. For example, if you want it to hang 12 inches, cut a piece 24 inches long.
Place a dab of glue on the styrofoam ball at the top; you will need to push the flower petals out of the way a bit to accomplish this.
Press the two cut ends of the ribbon to the glue before it dries. This creates a loop of ribbon with which you can carry or hang the pomander ball.