Houttuynia is the genus name for two ivy-like perennials, H. cordata and the newly-discovered H. emeiensis. It is native to the eastern sections of Asia, including China and Japan. In those regions, it can be found in shady, moist areas, such as marshes and woodlands. Although it is most often used as a ground cover, as a border in a garden, or as decoration along ornamental ponds and streams, it is also used in Chinese medicine.
The plant was named after a Dutch botanist of the 1700s, Martin Houttuyn. Houttuynia can be considered invasive, and it may have the tendency to overwhelm and strangle out other plants in a garden if it is left to its own devices. Consequently, care must be taken in selecting areas where this perennial is planted.
As a quick spreading perennial, Houttuynia has heart-shaped leaves that are gray-green or blue-green in color. There are some varieties that have variegated leaves that are comprised of several colors, such as green, yellow, cream, and red. Generally, the leaves range from about 1 inch (2.5 cm) to 4 inches (10.2 cm) in length. When the leaves are crushed, they emit an orange-like fragrance.
In the summer months, Houttuynia has dense spikes of small, yellow flowers. At the base of the yellow flowers, there are typically four to six white, petal-like bracts or modified leaves that are no longer than 0.5 inches (about 1.3 cm) in diameter. Some varieties of Houttuynia contain more petal-like bracts. For example, one variety, Flore Pleno, contains up to eight white bracts around the base of the yellow flower.
Most varieties of Houttuynia grow well in moist soil that is moderately fertile. Although the plants can grow in full sun or in partial shade, some varieties have a preference. For example, plants with variegated leaves often will have greener leaves if they are planted in shady areas. If those plants are grown in full sun, the leaves tend to be yellower in color.
Like many plants, Houttuynia has been used in the practice of Chinese medicine for years. It has properties in the leaves, stems, and roots that are antibacterial and antiviral, making it useful for the treatment of a wide range of infections. It is most often used to treat coughs, urinary tract infections, and vaginal infections. Some practitioners believe that it prevents the formation of tumors and fights cancer as well.