Convolvulaceae — Morning Glory Family
This morning-glory is an erect, sparsely branched shrub growing about 8 feet tall, unlike typical morning-glories that are vines. The leaves have a long stalk (petiole), and the essentially hairless leaf blades are lanceolate, 5 to 8 inches long, about 2 inches broad, and have a long-tapering tip and a truncated or shallowly heart-shaped base. The funnel-shaped flowers are borne in small clusters in the axils of the uppermost leaves. These flowers, opening only in the morning, have five shallow lobes and are 3 to 4 inches across. The fused petals are pink to lavender or purple, but darker in the throat.
The plant is native throughout much of tropical America, from Argentina to Mexico, and it has naturalized widely in the Old World tropics. In the United States, it has been reported from South Carolina, Georgia, Florida, Texas and Hawaii.
It has been collected in a variety of habitats, from maritime strands and dry fields to wet bottomlands and roadside ditches in a few South Florida counties.
The flowers of most morning-glories are basically similar in shape, and many are colored lavender or purple, but all other native and naturalized species are vines. This plant, a shrub, is quite distinctive, and it should not be confused with any other species.
Reclining stems in contact with the soil develop adventitious roots, and detached portions can grow into new plants. Suckers are produced as well. Cultivated plants usually produce seeds sparingly, but wild plants probably reproduce and spread primarily by means of seeds.
Ipomoea carnea is usually a vine with broad, heart-shaped leaves, growing in dry habitats; I. fistulosa is usually a shrub with narrow, lanceolate leaves, growing in wet habitats. Intermediates evidently occur, and Dr. Daniel Austin, a leading authority on the Convolvulaceae, concluded that they are not separate species, but rather subspecies of I. carnea. Only I. fistulosa (I. carnea subsp. fistulosa) occurs in Florida. This is a plant with a split personality. In its natural habitat, it prefers wet sites, and there it can form dense, impenetrable thickets. In cultivation, it grows in well-drained sites, and there it is a well-behaved, very ornamental shrub. The naturalized populations in Florida occur in both wet and dry habitats. The plant’s cold hardiness is uncertain, but since it grows in coastal South Carolina, it can evidently tolerate some degree of frost.
Although the plant has not yet become invasive, that potential exists, and the plant should be carefully monitored. It (as I. carnea subsp. fistulosa) is included on the FLEPPC List of Invasive Plant Species. As I. fistulosa, it is listed as a Class I Prohibited Aquatic by the state of Florida (Rule 5B-64.011, Florida Administrative Code), meaning its cultivation in Florida is prohibited and any movement of the species is possible only by permit from the Florida Department of Agriculture and Consumer Services.