Sounds like something straight out of a Harry Potter book, I know. But Spiderwort, which is also commonly called by its Latin name of Tradescantia virginiana, is anything but scary or dark. In fact, it is one of the most cheerful flowers in the garden in June.
This one will bloom in sun or shade, and its love of roadsides and abandoned spots along driveways belies a tough little garden plant. I was lucky enough to have some volunteer in my herb garden last year. I let it stay, and I have learned that this lovely little grass-like plant is a fantastic magnet for bees. They dance drunkenly all morning long at its blossoms, and the contrast of the yellow bees against the purple flowers is really a treat for the eye on a humid day.
These plants can take over, so be careful about placement. That said, they are awesome near compost bins, sheds, and driveways, because they rapidly fill in an empty space and block out other less desirable volunteer plants and weeds.