January 2017 Plant Profile: Chimonanthus praecox

Chimonanthus praecox, or wintersweet, is native to China. Its natural range is from the provinces of Hubei and eastern Sichuan to Zhejiang.

Chimonanthus praecox flower

In China Chimonanthus praecox is known as La Mei Hua and has been cultivated for more than 1000 years. In the 17th century it was introduced to Japan and it is also now known as Japanese allspice, though it has no relation to culinary Jamaican allspice, Pimenta dioica. Wintersweet arrived in Britain from China in the year 1766, according to a letter by Mr. William Dean, gardener to Lord Coventry at Croome Court, Worcester. And, the Lord Coventry reportedly being a generous man, wintersweet began its distribution throughout the western hemisphere. The genus name Chimonanthus is derived from Greek, meaning ‘winter flower,’ and the species name praecox comes from the Latin meaning early (precocious!).

Due to its sweetly fragrant flowers, wintersweet is one of the most popularly cultivated plants in temperate China. The flowers are used in potpourri as well as to scent linen, much as lavender is used in the United States. The essential oils are also used in cosmetics, perfumes and aromatherapy. For myself, the fragrance of Chimonanthus praecox comes in a clear and distant second place to Daphne bholua (also in the Witt Winter Garden), but I’ve found from visitors that this is quite debatable.
chimonanthus praecox flower cluster
The flowers are also used in herbal teas as well as in many Chinese folk remedies for ailments from coughs to measles. Much research is being conducted, particularly in China, on the health benefits of wintersweet due to the presence of antifungal, antioxidant and biocidal chemicals. Caution: the seeds of Chimonanthus praecox are not edible and contain a toxic alkaloid, Calycanthine.

Chimonanthus praecox is happy in full sun with moist soil and begins flowering in very late December continuing possibly to as late as March.  It is hardy to the low end of zone 7 (0 degrees), though near that temperature flowering will be later with the possibility of frost damage to flowers. Its habit varies from rangy to simply a bit untidy.  It is deciduous, thus the flowers are displayed prominently on naked stems. However, it is known to persistently hang on to 3% of its leaves as if to tease the most fastidious of us.

In my experience, Chimonanthus praecox responds well to aggressive renovation in early spring, vigorously producing many new stems. However, it seems to resent the insult, and flowering will remain sporadic for several years. This is in part due to the fact that flowers appear on the previous year’s wood. This does not fully explain the seemingly haphazard flowering in the years following hard pruning. It is also reported that a plant grown from seed may take up to 14 years to bloom for the first time. It may be one of those plants that just won’t bloom if it is growing vigorously. With all this in mind I would recommend light pruning only, after flowering, only as needed to maintain form and boundaries. If renovation is required, do not fear to be brutal, a healthy plant will return to fine form quickly- but beware its long memory.

Scientific Name: Chimonanthus praecox
Common Name: Wintersweet
Family: Calycanthaceae
Country of Origin: China
Location in the Arboretum: Joseph A, Witt Winter Garden. There are three mature specimens located throughout the Witt Winter Garden. The most prolific blooming specimen is located in the “twig bed” at the southwest corner of the garden.

Sources of Information

Jin-Shun Lv, “Chemical composition, antioxidant and antimicrobial activity of the extracts of the flowers of the Chinese plant Chimonanthus praecox”, Natural Product Research, Vol. 26 No. 14, 2012 pgs. 1363-1367

Ji-Wen Zhang, “Antifungal Activity of Alkaloids from the seeds of Chimonanthus praecox”, Chemistry and Biodiversity, Vol. 6 No. 6, June 2009 pgs. 838-845