Rose of Sharon: A Hardy Hibiscus

Hibiscus syriacus is a large, hardy, multi-stemmed deciduous shrub with showy Hibiscus-shaped flowers. Common names include Rose of Sharon, Hardy Hibiscus Shrub, and Shrub Althea. It’s popular in Western gardens because it flowers in late summer and fall, a time when most other shrubs are no longer in bloom.

Flowers have 5 petals, and in the wild are usually white, pink or light purple, often with a darker eye. The plant in our Japanese Garden has white flowers with red markings in the throat. It may be a seedling plant, but it looks very similar to the cultivars ‘Red Heart’ and ‘Helene.’ Flowers are short-lived, but mature plants produce many flowers.

Rose of Sharon leafs out very late, and leaves are medium-green, coarsely toothed and three-lobed. The yellow-green fall color is not ornamental. Plants are upright in habit, and often exceed 10 feet at maturity. Sun-loving, and tolerant of urban conditions, they’re easy to grow.

Native to China and India, not Syria, this shrub has been bred for hundreds of years. Cultivars produced include plants with semi-double & double flowers, and sterile, long-blooming plants that set minimal seed. On the other hand, plants grown from seed produce many fruits (brown, dry capsules, not soft berries) that germinate readily, so Rose of Sharon is often considered invasive – particularly in the Southeastern U.S. New cultivars are still being produced, distributed, and heavily marketed. These include dwarfs, doubles, and sterile forms.

Not common in Japanese gardens, Hibiscus syriacus has been used as a hedge, in a row or mass planting, and next to buildings. Fibers from the bark were used for making paper. Flower buds are edible, leaves were used to brew a substitute for tea, and various plant parts have been used for medicinal purposes.

Rose of Sharon is the national flower of South Korea, where it is known as mugunghwa. This derives from mugung, which means “eternity” or “inexhaustible abundance.” In Japan, it’s known as mukuge, and has been used to symbolize the impermanence of beauty.

Corinne Kennedy is a trained guide for Seattle Japanese Garden and a contributor to the garden's blog.