Native to Yemen, Exacum affine belongs to the gentian family and carries something of that lineage in its deep blue-to-purple flowers — showy, jewel-like, and produced over a notably long bloom period. It is a short-lived perennial in tropical conditions but is most often grown as an annual or as a potted plant elsewhere. Outdoors, it requires warmth, partial shade, and nighttime temperatures that stay between 60 and 70 degrees Fahrenheit; south-facing sheltered positions in humid subtropical gardens can meet those requirements, but much of its audience grows it indoors.

As a bedding plant in its native range it is used as a low ground cover, reaching only half a foot to a foot and a half tall, its shiny green foliage densely clothed in bloom when cultural conditions are right. It will not tolerate direct sun and is particular about drainage while needing consistent moisture — the same careful balance that governs most gentian relatives. Cuttings taken after flowering offer a way to continue it, since the parent plant is difficult to maintain once the blooming cycle ends.