Tropical, Hardy Hibiscus
Rose of Sharon, a hardy hibiscus, is quite similar to tropical ones and can be grown in many more areas.
The hibiscus flower worn behind the ear of a Tahitian beauty is not from Tahiti at all. It is actually native to Southeast Asia and was brought to the South Pacific by early traders. This icon of the tropical garden has been bred into dozens of luscious colors, but unless you live in Honolulu, Miami or Los Angeles, there's no way it will grow in your yard.
You might be surprised to discover that the genus Hibiscus contains another group that appears nearly identical to the tropical species. These alternates bear the same flower shape with the characteristic staminal column at the center of the flower that is less showy and smaller overall.
Plants are incredibly cold-hardy and winter well in parts of New England, where temperatures can drop to minus 15 degrees. It was mistakenly called the Syrian mallow, and named Hibiscus syriacus by Linnaeus, who thought this Chinese native originated in the Middle East. Its biblical name commonly used in the nursery trade is rose of Sharon.
What makes this shrub so neat is that its blossoms are nearly as showy as the tropical hibiscus'. They bloom for many weeks in late summer and into fall. Plants are big and vigorous, reaching 8 to 10 feet tall when mature. They are surprisingly drought-resistant for such a showy plant.
Breeders at the National Arboretum used the white-flowered species to develop a greater range of color. What resulted were incredible hybrids that make first-class garden shrubs. The new hybrids not only produce different colors, but they feature double flowers with twice as many petals as their predecessors. An inner "eye" of darker accent at the base of each petal makes the bright yellow staminal column stand out better in high contrast.
The National Arboretum hybrids are all named for Greek goddesses, which makes them easy to remember. Showy 'Aphrodite' produces a deep rose-pink flower with a dark-red eye. Modest 'Diana' is white with no accent color, which makes a super moon-garden choice. Traditional 'Helene' is white with a burgundy eye. Romantic 'Minerva' is lavender-pink with a purple eye. Hybrids by other breeders produced 'Blue Bird', with flowers in a violet-blue coloring, available in single or double forms.
The key to using this plant in the garden is to respect its size. If planted where space is limited, you'll be cutting it back all summer to keep it in bounds. Since it blooms so late, this will cut off all the flower buds and sacrifice blooms. However, the plant's branching structure is naturally upright so it won't spread out more than about 6 feet.
This branching makes the rose of Sharon a good screening plant for narrow side yards. Plant it against the fence in front of windows to increase indoor privacy in adjacent rooms. Then throw open the shades to view the flowers close up, where their exotic colors, eyes and stamens are best appreciated.
Try rose of Sharon along fence lines or as a backgrounder for shrub and perennial borders. It makes a fine single specimen against a large bare wall of the house or garage. It also makes a superior candidate for swimming-pool areas as a screen or to disguise unsightly safety fencing.
If you're new to gardening and are looking for plants that give you a big bang for your buck, invest in rose of Sharon hybrids. With the right location and a little care, that $6 shrub will soon look like a million bucks.