It’s difficult not to love Rose of Sharon. Also known as hardy hibiscus or althea, this hardy perennial produces spectacular, cup-shaped, single or double blooms in various shades of reddish-purple, pink, red or white for most of the summer. Even better, the plant creates all this beauty with very little assistance from you.
Growing Conditions: Suitable for Almost Everywhere
Rose of Sharon is happy in most climates and gardeners in USDA growing zones 5 through 9 can grow this impressive plant with no worries. The plant needs at least four hours of daily sunlight, but a little afternoon shade is a good thing, especially if you live in a hot climate.
Similarly, nearly any soil is fine, although the plant may rebel in bone dry or soaking wet conditions.
Rose of Sharon is easy to propagate – maybe a little too much so. Although you can plant seeds, cuttings are easy to root in winter, and the young plants are usually ready to go outdoors the next fall. If you have stray seedlings from an established plant, you can always transplant them to a different location or pot them up and give them away.
Rose of Sharon loves heat and grows relatively quickly. Once established, an occasional deep watering is all it needs.
Watch for thrips, which are usually easy to control with regular applications of insecticidal soap.
Pruning: Tree or a Shrub?
Rose of Sharon is basically a shrub that reaches heights of 10 to 12 feet, but with a little pruning, it can also be a smallish tree. Just remove the lower limbs in late winter or early spring to form a single trunk.
Whether you grow Rose of Sharon as a tree or a shrub, the plant will likely be covered with masses of blooms. However, some gardeners like to prune to two or three flowers per stem to create impressive, 5-inch flowers. This, like the tree vs. shrub question, is a totally your choice.
Downside: Rose of Sharon as Invasive Species
Rose of Sharon is native to China and India, which means it is a non-native species and, as such, can be weedy. According to the USDA Forest Service, Rose of Sharon has outgrown its welcome across most of the eastern and southeastern United States. It is officially considered an invasive species in Pennsylvania, Kentucky, Virginia and Tennessee, where it crowds out desirable native plants.
Consider carefully before planting Rose of Sharon in these areas. The plant is a prolific self-seeder with a hefty taproot and you may find yourself digging, pulling, and spraying unwanted seedlings in two or three years. If in doubt, check with your local Cooperative Extension office about the status of the plant in your area.
Keep in mind, however, that Rose of Sharon is relatively well-behaved in many areas, and its hardiness makes it a great choice for a hedge or border. Also, ask at your local nursery about availability of sterile cultivars such as ‘Minerva,’ ‘Helene,’ and ‘Diana.’ These, and other varieties of Rose of Sharon are also available for purchase online at www.NatureHills.com.