By Bodie Pennisi
University of Georgia
The individual petals of the giant blossoms are more divided that other species of hibiscus, giving the blooms a star shape. Each flower lasts only a day, but new blooms open throughout the summer and fall.
The leaves are deeply divided into narrow, toothed, finger-like lobes. The foliage adds its own remarkable statement for an overall bold, tropical effect all summer long. Established plants easily reach 7 feet in tall in a single growing season.
A native to the Southeastern United States, swamp hibiscuses prefer a sunny spot in the garden and well-drained soil containing organic matter. Under these conditions, the plants will reward you with the most vigorous growth.
WaterPlenty of water is necessary for the most abundant blooming. Hibiscuses will tolerate light shade and less desirable soils, but their vigor and flowering will be less.
Naturally growing in swamps and bogs, swamp hibiscuses will be an excellent addition to a water garden, as its roots will tolerate even some flooding.
Plant swamp hibiscuses where they're not exposed to strong winds to avoid breaking the long stems. If some stems break, you can trim them and new side shoots will grow and produce more blooms.
To encourage reblooming, deadhead spent flowers before they form seedpods, or prune plants back by one-third after a flush of bloom is finished.
Perennial hibiscuses freeze back to the ground in the winter and resprout in mid-spring. Old stems can then be cut back to the ground.
Hibiscus is easy to propagate by seed, cuttings or division. Collect the seeds from dried pods that have started to split. Sow the seeds indoors three months before the last spring frost. Soak the seeds in very warm water for one hour before you sow them.
Pencil-thick, 5- to 6-inch long cuttings from greenwood taken in the spring will root the fastest. Plants can be divided in the early spring.
Georgia Gold Medal winners are chosen once a year for their consumer appeal, low maintenance, survivability, ease of propagation and seasonal interest. It's easy to see why swamp hibiscus is the 2007 winner for herbaceous perennials.
(Bodie Pennisi is a Cooperative Extension floriculture specialist with the University of Georgia College of Agricultural and Environmental Sciences.)