Fill the tall vase half full with water. If you have some cut plant food, sprinkle it into the water and stir until it is dissolved.
Place the bear grass leaves into the centerpiece, letting the leaves naturally hang from the vase.
Cut the large yellow flowers to three heights. Relative to the vase, you’ll want tall, medium and short flowers. Cut the red flowers to two heights between the yellow flower heights.
Place the flowers into the vase and arrange them so that the grass is in the middle of the centerpiece and the flowers are arranged at the various heights around the grass.