Hibiscus mutabilis 'Rubrum'

Hibiscus mutabilis has been grown in Southern gardens for so long that many people assume the shrub is a native, though the species traces to southern China, where gardeners prized the flowers centuries before the plant traveled west. The species name mutabilis, meaning changeable, describes the wild trick of the ordinary Confederate Rose, whose blooms open white in the morning and deepen to pink and then rose-red by evening. 'Rubrum' skips the performance and commits: the single flowers arrive already a saturated rose-red and hold that one deep tone through the day rather than shifting. For gardeners who love the late-season drama of the Confederate Rose but want a single, unwavering color, 'Rubrum' is the selection to plant.

The shrub belongs to the mallow family, Malvaceae, and shares that clan's signature: a prominent central column of fused stamens rising from the throat of a broad, five-petaled flower. Cotton, okra, and hollyhock are all cousins, and the kinship shows in the softly downy, maple-shaped leaves and the fuzzy seed capsules that earned the alternate common name, Cotton Rose. In the Deep South, 'Rubrum' builds into a large, multi-stemmed shrub of six to eight feet in a single season, flowering in the shortening days of late summer and fall when much of the garden has already gone quiet.

Beyond ornament, Hibiscus mutabilis carries a long medicinal history in China, where the plant is known as Mu Fu Rong. Traditional practitioners used the cooling leaves and flowers as poultices for burns, boils, and inflamed skin, and brewed them for coughs and respiratory complaints. Modern laboratory work has taken an interest in these old uses, isolating anti-inflammatory flavonoids from the flowers and an antiviral compound, tiliroside, from the plant, lending some scientific texture to a tradition many centuries old.

In the garden, give 'Rubrum' room and a backdrop. The tall, upright shrub reads best from a slight distance, at the back of a sunny border or as a freestanding specimen where the autumn flowers can carry the eye across the yard. Late-blooming salvias, ornamental grasses at mature height, and anything with a quiet green or silver leaf make good neighbors, since the rose-red flowers want a calm setting rather than competition. In the colder end of the range the shrub may die back to the ground in winter and return from the roots, so pair the plant with something that fills the early-season gap. If the common name Confederate Rose sits uneasily, Cotton Rose is the older, equally accurate alternative, and either name points to the same generous, late-flowering shrub.