Plants in the genus Chimonanthus often have the common name wintersweet because they usually bloom in the winter and have fragrant flowers. Chimonanthus is a genus of the Calycanthaceae family, called the spicebush or sweetshrub family. These plants, which are native to parts of China, are shrubs that gardeners usually value for their winter blooms more than their foliage. Parts of the plants have medicinal value, and companies use the plant oils for cosmetics and other applications.
Generally, the flowers are waxy and often pendent, which means they hang upside down. They range in color from white to bright yellow ranging to deeper yellow. Often the flowers have maroon or brown staining at the base of the inner flower. The flowers do not have proper petals; they have tepals, which are petal-like, but the calyx and corolla are not separate. The flowers may be resemble bells, bowls, or plates, and the tepals may be shaped like spoons, striped or spidery or crimped or twisted.
A gardener might want to research which wintersweet he or she is purchasing because the name refers to more than one plant. This includes a few species of trees from South Africa in the genus Acocanthera, a dwarf shrub from Crete named Origanum dictamnus, and Origanum vulgare, or wild marjoram. Some literature and websites refer to Chimonanthus plants as Japanese allspice.
The species C. nitens is native to parts of China and Japan. Its evergreen leaves are dark green on top and a lighter green on the underside. Its white flowers' spidery tepals are unstained and less fragrant than those of most species. Growers use it as a container plant with proper pruning. It grows to heights of 10 to 15 feet (3 to 4.6 m) tall and 6 to 8 feet (1.2 to 2.4 m) wide in its natural setting.
Some of the Chimonanthus cultivars include concolor, which is also called luteus, grandiflorus, and parviflorus. Concolor has translucent, yellow flowers that are generally open wider, but are unstained. It usually blooms earlier in the winter season. Grandiflorus also has large flowers that sometimes measure 1.75 inches (4.5 cm) across and are a deep yellow with stripes of deep red or maroon inside. Parviflorus has very small, pale yellow to cream-colored flowers.
One of the more popular Chimonanthus species is the C. praecox, a deciduous, upright shrub that sports willow-like, lance-shaped leaves. These leaves typically are glossy, mid-green colored, and average up to 8 inches (20 cm) long. The bright yellow flowers have a red, brown, or purple stain on the inside. White pollen covers the stamens, which contrast attractively against the dark stain.
During the winter, there usually are no insects available to pollinate plants. One or two days after a bloom opens, the five stamens fold themselves over the stigma, self-pollinating the plant. Growers propagate the plants by sowing the seeds or by rooting softwood cuttings.
Chimonanthus plants have essential oils that manufacturers use in cosmetics, perfumes, and aromatherapy. For centuries, native herbalists have used parts of the plants, especially the root, to treat heatstroke, cough, and bruises and burns. They also brewed tea from the dried leaves. Scientists are studying the plant's antifungal and antibacterial attributes.