Need help with very long and narrow flower bed
Half of our backyard is a vegetable garden with citrus trees off to one side. On the other side of the citrus tress sits my flower bed which is cinder block, runs the length of the garden and separates the garden from the backyard lawn. The flower bed is 30 feet long and 20 inches wide and has good drainage. It runs east to west, and gets full sun on the north side of the house in direct view of our bedroom windows. Need ideas of what flowers would work best with the citrus trees as a back drop with such a narrow work space. Butterflies and humming birds would be welcome visitors.