Yellow flowers attract bees through their coloration. Bees use the colors in flower blossoms to help them distinguish the blossoms from grass and other non-flowering plants in the field.  Many flowers bloom in yellow because yellow is one of the easiest colors for bees to perceive with their vision.  Bees base their visual colors on blue, green, and ultraviolet lights. Bees can't perceive the color red, which means that plants with red blossoms rarely depend on bees for pollination in nature. In comparison, many plants with yellow blooms depend on bees to reproduce.