Highly prized for its propensity to produce large flowers of various, vibrant colors, the rose of Sharon, a large shrub or small tree, is best known for thriving in tropical or warm Mediterranean locales. As a result, it enjoys large amounts of sunshine and rewards gardeners with flowers that bloom on a daily basis.
The rose of Sharon (Hibiscus syriacus) enjoys full sun to partial shade. Also known as Shrub Althea, the plant is considered hardy to USDA Hardiness zones 5 through 9, an area that encompasses much of the U.S. aside from the upper Midwest. While it will grow in shade, it requires -- at the least -- an alternating mix of sun rays.
To achieve its prime flowering capability, the rose of Sharon demands ample moisture and a bit of protection from the midday and afternoon sun. The shrub tolerates many soil conditions and an acidic to alkaline pH level in the earth. The branches of the tree grow upright and typically do not droop except when in the flowering stage. It maintains an upright form as it grows, so very little pruning is necessary.
When planting this shrub, allow for significant room. With plenty of sunshine, the rose of Sharon can grow to a height of 8 feet with a width of 6 to 10 feet. Native to India and China, the plant is something of a tease; while gardeners may worry that the shrub is failing to grow due to a lack of spring or summer sunshine, the rose of Sharon has something else in mind; it routinely fails to turn green in the spring and normally waits until August or September to begin flowering.
The rose of Sharon dates to Biblical times and is prominently featured in “Song of Songs.” In this section of the Bible, King Solomon alluded to his beautiful lover as a “rose of Sharon.” This serves as a metaphor to the plain of Sharon, a swath of land near Jerusalem, recognized for its fertility and pretty flowers. "I am a rose of Sharon, a lily of the valleys," reads part of Song of Solomon 2:1.