Black Bat Flower (Tacca chantrieri) looks out of this world. The unique bat-shaped flowers can grow 12" across with "whiskers" that are 28-inches long. Bat flowers bloom in August-September. This intriguing plant is from the Yunnan Province, China. It gets 36" inches tall. Bat flowers are hardy in zones 10-11. There is also a white form. Bat flowers are at home in sunrooms, greenhouses or on hot, humid shady porches. Plant them in well-drained soil.
These and the other black plants shown below are available from Van Bourgondien and may be purchased at http://www.dutchbulbs.com/.
Giant Dinner Plate Dahlias add a lot of drama to the back of the border in late summer and fall. 'Black Wizard' has deep maroon-black 8"-10" blooms. Dahlias make wonderful cut flowers. 'Black Wizard' dahlias are hardy in zones 8-10. Dig and store them in a frost-free location during the winter if you live in a colder zone.
'Black Magic' Elephant Ears (Colocasia esculenta 'Black Magic') have gigantic tropical foliage that will leave gardeners spellbound. 'Black Magic' gets 40"-45" tall in part shade and moist soil. It is hardy in zones 10-11. Lift and store bulbs indoors during winter in colder parts of the country...
Who doesn't love low-maintenance daylilies (Hemerocallis) in the sunny border? 'Black Stockings' has large, dark purple-black flowers. It is a mid-season rebloomer and is semi-evergreen. 'Black Stockings' grow 25"-30" high.