Rose of Sharon (Hibiscus syriacus) is a deciduous shrub that brings a bit of tropical beauty to more temperate climates. It features a vase-shaped form that grows from 10 to 15 feet high with a spread of three to six feet. Depending on the cultivar, the flowers range from white to deep pinkish purple.
Don't confuse this plant with Chinese hibiscus (Hibiscus rosa-sinensis), which is its cousin. They may look similar, but Rose of Sharon is temperate, while Chinese hibiscus is decidedly tropical.
Rose of Sharon, whose common names also include Althaea, Shrub Althea and Hardy Hibiscus, belongs to the Malvaceae (mallow) family.
Growing Rose of Sharon
Rose of Sharon is rated for zones Zones 5 to 9 and grows best in full sun, although it can tolerate part shade. It prefers moist, well-drained soils, but grows easily and can adapt to almost any soil. Rose of Sharon is somewhat tolerant of drought conditions.
In the cooler zones (where the temperatures fall below 10 degrees Fahrenheit in winter), be sure to mulch around the plant well during the winter season.
Don't be surprised if your Rose of Sharon is the last to leaf out in the spring. Leaves are two to four inches long, often with three lobes, and jagged edges.
The flowers bloom in mid to late summer and are two to five inches wide, in shades of white, pink, red, blue, purple, and violet. There is often a different spot of color in the middle of the throat.
If you have hot summers, you are in luck; Rose of Sharon prefers the heat and will bloom more profusely.
Maintenance and Pruning
Rose of Sharon can be trained as a small tree or espalier, or allowed to grow into a large shrub. It responds well to heavy pruning, so there are many options for customizing it to fit your garden, including clipping it into a hedge.
Prune as needed to maintain the shape desired. In winter or early spring, last season's growth should be pruned away, which will help produce bigger blooms.
You can easily propagate this plant from stem cuttings, and you can also grow it from saved seed, although the seedlings' flowers may not be true to its parent's. In some areas and growing conditions, this plant is considered invasive. If you notice seedlings popping up around the plant, you can control them by snipping them off before they open.
Rose of Sharon is available in many varieties, generally categorized by the color of flower. Popular varieties include:
- Diana, a profuse white-flowered bloomer whose single petals remain open at night
- Lucy, a red-and-pink variety with double petals
- Aphrodite with thick, lacy petals and a red center
- Minerva with lavender-mauve single flowers, each with a red eye
Pests and Diseases
Diseases include leaf spot, blight, and cankers.