Beginner Gardening: ideas for half barrels, 1 by katboyd

katboyd wrote:
I am planning to plant some flowers in two half barrels that sit in front of my brownstone apartment building (I rent the ground-level apartment). The half barrels get about 4 hours of full sun a day, and each already contains a boxwood (see photo). My objective is to add a little color to a rather drab-looking area, so ideally I would like flowers that would bloom all summer. I'm not sure what would look right with the boxwoods and would love to hear any ideas to help get me started. Thanks!!