Fortnight Lily

Scientific Name: Dietes bicolor

Fact Box:

  • Order: Asparagales
  • Family: Iridaceae
  • Genus: Dietes
  • Species: D. bicolor


Perched atop a long, thin stalk is a cream-colored flower with three reddish-black markings on it. Named fortnight lily (or African Iris), this flower is native to South Africa. The plant gets its common name from its flowering cycle, which is every two weeks, or a fortnight. The flower is a member of the Iridaceae, or iris, family and has three “outside” petals and three “inside” petals like other irises. With rhizomes — horizontal roots that can produce new vertical shoots — these plants are difficult to remove once they are grown.


Although the plant is easily identifiable for its markings, the genus of the plant was once not so clear. Fitting both the Northern Hemisphere genus Iris and the African genus Moraea, the genus of the fortnight lily perplexed botanists at first. (Later, scientists decided that the plant fell under the Dietes genus of the Iris family.) Because of the mix-up, the genus name Dietes was coined from the word “dis,” meaning double or two — in this case, two possible genera (the plural of genus).


Traditional African healers used this plant to reduce diarrhea, while some Africans wore the flower as a protecting charm. Another intriguing fact is that despite blooming from October to January, each flower only opens for one day. New buds that bloom every day hide this fact.

One other note-worthy fact is that the fortnight lily is used in firescaping, meaning landscaping with wildfire-resistance in mind; flowers planted in this design are difficult to catch on fire. Besides tolerating flames, some fortnight lily flowers glow in the dark!