Hummingbirds are particularly fond of bright reds, purple, white, pink, orange and blue. Bee Balm and Cardinal Flower are two of the hummingbirds' favorite nectar sources. These plants, however, don't have a long bloom life, so it is important to add a variety of nectar-bearing flowers to ensure a longer feeding season. Hummingbirds may be small, but they pack a lot energy in those tiny bodies.