Okay, I know that these ARE Morning Glories, but the color reminded me of the Witching Hour. Too bad that we couldn't get them to bloom in the moonlight!
Details... "Morning Glory, black-purple flowers with a cerise throat in abundance on this climber to 4 feet, flowers from July to October. Easy to germinate and grow, very heat tolerant prefers full sun. If transplanting, start indoors 5-6 weeks before transplant and harden-off before final placement. Direct sow after danger of frost."