A tender garden annual turning black at the first frost. Planting sooner than Memorial Day weekend may be risky (zone #5).
purple, an inflorescence of clusters of tubular flowers
simple, green, opposite, heart shaped
As the flowers die they need to be dead headed which is no easy task. Flowers are on short scapes and are hard to remove. This is one plant I don't enjoy the task of dead heading.
Native to Mexico and Central and South America
Named after William Houston who collected the species in the Antilles and Mexico.
Notes & Reference
#27-Rodale's Annual Gardens (Paul Loewer),
#28-Cottage Garden Annuals(Clive Lane), #51-Armitage's Manual of Annuals, Biennials and Half-Hardy Perennials (Alan Arimitage), #109-Annuals and Tender Perennials for North American Gardens (Wayne Winterroud)