Despite its name, the deciduous flowering shrub we call rose of Sharon isn’t a rose at all. Native to Asia and India, this plant with exotic-looking blooms is actually a hibiscus (Hibiscus syriacus), a member of the mallow family. Other common names include shrub althea, Chinese hibiscus and hardy hibiscus. Rose of Sharon is mentioned in the Old Testament, although scholars think that the reference, which appears in the Song of Solomon, is a mistranslation of a Hebrew word for crocus.
Shakespeare wrote, “a rose by any other name would smell as sweet,” and rose of Sharon, no matter what name you call it, is lovely. The large single or doubled flowers are often wavy-looking, giving the impression that they’re made of crepe paper. They open in late summer to fall, when few other shrubs are in bloom. Depending on the variety, the flowers may be violet, blue, pink, red, lavender, purple or white, and they often have a dark “eye” in the center.
Hardy to USDA zones 5 to 8, rose of Sharon is an easy-to-grow, undemanding plant, happy in full sun to part shade. It prefers moist, well-drained soil but is tolerant of many growing conditions, including periods of drought and exposure to pollution, which makes it excellent for urban gardens. Few pests damage the plants, with the exception of Japanese beetles.
Rose of Sharon can be planted in spring or fall; the plants tend to leaf out somewhat late in springtime, so don’t be alarmed if yours gets off to a slow start in the growing season.
Amend the planting hole with some compost and water thoroughly after filling the hole to eliminate any air pockets and settle the soil. Add a layer of mulch each spring to help keep moisture in the soil and prevent weeds from sprouting.
Mix a general-purpose fertilizer into the soil when you plant, following the product directions, and water it in well. Fertilize again each spring. But avoid overfeeding your rose of Sharon, which can cause the leaves to turn brown or yellow and drop. Over-fertilizing can also promote foliage growth at the expense of flowers.
Prune in late winter or very early spring, if you want to control the size of your plants. Cutting back to two or three buds per branch will help encourage larger flowers. Some gardeners simply let their plants grow naturally, although taller plants typically have smaller blooms. Just don’t prune in the summer. Since rose of Sharon blooms on the current season’s wood (new wood), you’ll be removing your flowers.
Rose of Sharon attracts butterflies and hummingbirds. Try the plants in a straight line to create a hedge or living fence, or use them as a backdrop for shorter shrubs and flowers. Space the plants 6 to 10 feet apart; spacing depends on the size they are expected to reach at maturity, so read the tags or labels. Rose of Sharon also makes an excellent low-maintenance potted plant.
A single rose of Sharon can add interest to a corner of the garden or create a sense of height in a flowerbed. To train it as a small tree, prune the canopy to about one foot above the ground. Prune again each year to maintain the size and shape.