Hibiscus rosa-sinensis, or “Chinese Hibiscus,” of the family Malvaceae. Originally, the Chinese hibiscus is from southeastern Asia (Ross, 2003). In Latin, “rosa-sinensis” translates into English as “Chinese rose” (Forsling, 2013). This plant can be found in tropical regions or as a common houseplant in areas with temperatures warmer than 12 degrees Celsius (Curler, 2011).
This plant may grow as an evergreen shrub in gardens to heights of 8 feet tall, or even up to 15 feet tall as a tree in the tropics (Dvorkin & Whelan, 2004). Its green leaves are 6 inches long and are shiny, smooth, flat and egg shaped (or ovoid), while its five overlapping petals may range in size from 2 to 5 inches long (Dvorkin & Whelan, 2004). The flower is solitary, and many hybrids exist today with variously coloured petals from bright red to orange to purple (Kwantlen Polytechnic University, 2012). The fruits are rarely formed, but when they do appear, they exist as a dry 5-lobed capsule each containing 3 seeds (Ross, 2003). Some native varieties have been documented to live for more than 50 years while present-day hybrids have significantly shorter lives of 5 to 10 years (Forsling, 2013).
The Chinese hibiscus is a tropical plant that needs both light and heat to thrive (Forsling, 2013). They like a few hours of direct sunshine every day, prefer moderate heat and will not tolerate frost (Forsling, 2013). However, this has not stopped people from growing the Chinese Hibiscus in cooler areas such as Canada and Northern Europe; one grows the plant in a pot instead of in the ground so that it may be brought inside to avoid catching frostbite during the winter months (Forsling, 2013). In addition, this plant also requires thorough watering although the soil should be dry before the next watering, to prevent root rot (Missouri Botanical Garden, n.d). While the Chinese hibiscus has a good root system, they should be grown in soil that is well-drained and retains moisture (Forsling, 2013). The most common pests are spider mites and aphids, but spraying the underside of the leaves daily with water or an insecticidal soapy solution can circumvent issues (University of Minnesota, 1998).
Once the buds have been established in a new plant, which takes a few weeks, it will start to bloom and produce flowers (Missouri Botanical Garden, n.d). Note that this plant will only bloom when it is in direct sunlight (Curler, 2011). While the flowers last for about a day, new ones will have bloomed in their place by the next day (Missouri Botanical Garden, n.d). The Chinese hibiscusproduces flowers on new shoots, thus pruning the plant will stimulate budding, especially if one gets rid of feeble growths and branches that are growing sideways (Forsling, 2013). The flower is pollinated by hummingbirds and butterflies, and has pollen that can be seen with the naked eye (Forsling, 2013).
While mainly used as an ornamental shrub, Chinese Hibiscus may also have use in medications for humans due to its antibacterial activity (Ruban & Gajalakshmi, 2012). Extractions from the plant material have been shown to inhibit the bacterial growth of human pathogens such as Bacillus subtillis and Escherichia coli; however, further research needs to be conducted before being used in drugs (Ruban & Gajalakshmi, 2012).
Curler, M. (2011). Hibiscus rosa-sinensis. University of Wisconsin La Crosse. Retrieved from http://bioweb.uwlax.edu/bio203/2011/curler_meli/index.htm
Dvorkin, L., Whelan, J. (2004). Boston University School of Medicine. Retrieved from http://www.bu.edu/bhlp/Clinical/cross-cultural/herbal_index/herbs/Hibiscus%20Rosa%20Sinensis.html
Forsling, Y. (2013). Hibiscus. Retrieved from http://hibiscus-sinensis.com/hibiscus.html
Hibiscus rosa-sinensis. (n.d). Missouri Botanical Garden. Retrieved from http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode
Hibiscus rosa-sinensis L. (n.d). Plants for a future. Retrieved from http://www.pfaf.org/user/Plant.aspx?LatinName=Hibiscus+rosa-sinensis
Hibiscus rosa-sinensis. (2007). National Tropical Botanical Garden. Retrieved from http://ntbg.org/plants/plant_details.php?plantid=6229
Kwantlen Polytechnic University. (2012). School of Horticulture Plant Database. Retrieved from https://plantdatabase.kwantlen.ca/plant/plantDetail/77
Ross, I. A. (2003). Hibiscus rosa-sinensis. Medicinal Plants of the World 1: 253-266.
Ruban, P., Gajalakshmi, K. (2012). In vitro antibacterial activity of Hibiscus rosa-sinensis flower extract against human pathogens. Asian Pacific Journal of Tropical Biomedicine 2: 399-403.
University of Minnesota. (1998). Hibiscus. Retrieved from http://www1.extension.umn.edu/garden/yard-garden/houseplants/hibiscus/