The Bourbon rose first appeared in the 1800s on the Isle of Bourbon (now Reunion) in the Indian Ocean. Bourbons bear large, full blooms that have a very heavy fragrance. They are extremely vigorous, producing shrubs that are big, wide, and very adaptable for training as pillar roses or on a fence. Most rebloom very reliably in colors that range from white to deep pink to scarlet. Bourbons are hardy to zone 4 and may survive colder climates with winter protection. Bourbons are occasionally subject to blackspot and mildew, which is not a major drawback because of the overall vigor of the shrub.