Perhaps there is no more blue flower than desert blue bells. An excellent and long blooming hardy annual that is at home in container as well as the ground. Often it will reseed prolifically from just one pot. To 6″ tall and as wide. Full sun and rich to average well drained soil. Light, consistent summer water keeps it going. Otherwise it will go away but not before setting seed for the following season. The vivid blue bell shaped flowers attract pollinators. Good western wildflower.