Scutellaria leonardii (small skullcap)

At only four inches tall, this member of the mint family thrives in dry, sunny sites like terrace gardens (aka hellstrips). Native bees visit for nectar and pollen. Spreads by seed and rhizome to form dense colonies. Pairs well with other short sun-lovers like wild petunia, prairie smoke, pussytoes, and prairie blue-eyed grass. 

Photo 1, Photo 2, Photo 3, Photo 4: Frank Mayfield / CC BY-SA 2.0