This is a tender garden annual turning black at the first frost. Planting sooner than Memorial Day weekend may be risky (zone #5)
small 1/4-1/2" tubulor flowers are in clusters forming a fluffy ball, color is blue, also rose, pink and white
simple, green, opposite, heart shaped
As the flowers die they need to be dead headed which is no easy task. Many of the cultivars flowers are on short scapes and are hard to remove. This is one plant I don't enjoy the task of dead heading.
small seeds should be start 6-8 weeks before they are going to be planted in the garden.
Native to Mexico and Central and South America
Names 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 America Gardens (Wayne Winterroud))