Yes, some hibiscuses are hardy in Louisiana. One of them, the Luna series hibiscus, has been named a Louisiana Super Plant selection for spring 2014.
Louisiana gardeners have long loved the tropical hibiscus, Hibiscus rosa-sinensis. These evergreen shrubs with dark, glossy leaves and large, flamboyant flowers in shades of red, gold, orange, yellow, pink and white are popular in pots and in the ground. But as this past winter has clearly shown, the tropical hibiscus is not reliably hardy when planted in the ground.
Hardy hibiscuses are quite different when compared with tropical hibiscuses. The flowers are usually much larger, ranging in size from 6 to 12 inches across. But the color range is more limited – primarily shades of red, rose, pink and white. The leaves are larger and are dull rather than shiny and are generally light to medium green. The bushy plants grow vigorously and range in size from 2 to 3 feet up to 5 or 6 feet in height.
When fall arrives, around October, the plants stop growing and begin to go dormant. All of the upper growth dies back to the ground; only the crowns and roots remain alive over winter. They will survive even the harshest winter throughout the state and reliably return each year for many years. New growth generally appears in March or April, and blooming begins in May and lasts until September or October.
The hardy hibiscus is also called mallow, rose mallow and swamp rose mallow. The Latin name most often used when referring to these plants is Hibiscus moscheutos. But the varieties you find in the nursery trade are generally hybrids of this species with several other hibiscus species native to the Southeast. You can often see these wild species blooming in boggy areas and roadside ditches with large, showy flowers throughout the summer.
The native parentage of the cultivated hardy hibiscuses means they are well adapted to our climate. They thrive in the heat and humidity of the Louisiana summer.
During the summer you will find a number of named varieties such as Lord Baltimore, Kopper King, Peppermint Schnapps and Blue River II available in nurseries. Popular seed-grown series have been Southern Belle and the dwarf Disco Belle. The new Luna series supersedes and replaces the Disco Belle.
The Luna series hibiscus was released a number of years ago. In trials at the LSU AgCenter Hammond Research Station and from observation of plantings in Louisiana landscapes, its superior qualities became apparent. As a result, it was selected to be a Louisiana Super Plant for spring 2014.
The notable characteristics include large flowers produced generously on full, compact plants.
The five-petaled flowers are 7 to 8 inches across and very showy. The four colors in the series are Luna Red, Luna Swirl (dark and light pink in a swirling pattern), Luna Rose and Luna White (pure white with a red eye). Flowering runs from late spring to early fall.
Rose mallows can be tall and somewhat rangy, but the Luna series hibiscus is compact, with a nice branching habit that produces a full, shapely bush. The bushes generally grow about 2 to 3 feet tall and about 2 feet wide. The leaves are medium green, slightly fuzzy, heart-shaped and about 5 inches long.
Like all the hardy hibiscuses, Luna hibiscuses are long-lived perennials that return for many years. The plants die down in fall and are dormant over the winter. New growth emerges from the ground in April.
Luna hibiscuses are often available as blooming plants at local nurseries in late spring and early summer. Look for them now and over the next few weeks. They are also easy to grow from seeds and will bloom the first year from a spring or early summer planting.
When you plant a Luna hibiscus, select a location that receives plenty of direct sun – at least six hours or more will produce the most flowers. Plants may be placed in typical well-prepared garden beds as you would other summer bedding plants. They look great in the back of a bed with shorter-growing bedding plants in front of them. You may also grow them in containers on patios, porches or decks.
These hibiscuses will thrive in boggy areas or even shallow standing water – just as you see their ancestors growing in the wild. Luna hibiscuses flourish on the edges of ponds, in low, wet areas or in rain gardens. You can even set pots directly into aquatic gardens with the rim of the pot 2 or 3 inches below the water surface.
Luna hibiscuses are attractive to butterflies and hummingbirds and make a dramatic addition to the summer flower gardens. You definitely should give them a try in your gardens this year.
Home gardeners and professional horticulturists alike are benefitting from using Louisiana Super Plants. Selected plants have a proven track record, having gone through several years of university evaluations and/or years of observations by landscape industry professionals. Louisiana Super Plants are “university tested and industry approved.”
More information on the program, selections and where you can buy the plants is available online at www.lsuagcenter.com/superplants.
Dan Gill is a horticulturist with the LSU AgCenter. He can be reached at DGill@agcenter.lsu.edu