There are only two species of plants that fall under the genus name of Kirengeshoma: K. palmate and K. coreana. These perennials are typically found with clumps of large, green leaves with yellow, bell-shaped flowers. They are native to both Korea and Japan and prefer to live in a woodland environment. They are becoming more popular and they are hard to grow from seed, making plants in this genus difficult to find and quite expensive.
Both Kirengeshoma species grow well in moist areas that are partially shaded and protected from the wind. If the soil is acidic, Kirengeshoma seem to thrive. In addition, the only true pests to this genus of plant are snails and slugs, which eat Kirengeshoma leaves. Although they can survive in colder environments, even in temperatures dipping to -20° Fahrenheit (-28.8° Celsius), they may require winter mulch for protection. Conversely, if the temperatures are too warm, they may become dormant and not produce any blooms in the spring or summer months.
One of the two species of Kirengeshoma is K. palmate. The plant is commonly called yellow wax bells and can grow up to 5 feet (1.52 m) tall. It has red or purple stems and broad, mildly hairy leaves. The flowers usually grow in groups of three and are yellow in color. They are bell-shaped and hang downward, especially as the summer months are ending.
The other species of Kirengeshoma, K. coreana, is slightly more rare than K. palmate. The flowers are a lighter shade of yellow, and the blooms are wider and directed upward. When the bell-shaped flowers open, they appear to look more like pale yellow stars. This plant can grow to be 3 feet (0.91 m) tall. To many people, the two species look almost identical.
The Kirengeshoma plants can easily be separated to increase the number of plants in the garden. Generally, they should be divided in the spring or fall, depending on the climate of the area. Although it is possible to grow them from seeds, they typically wither and die when they are transplanted.
Many people plant them along with other partial shade perennials, particularly since they are resistant to many pests and diseases. As long as they are given ample water and have fertile, slightly acidic soil, they generally grow well in most areas. Many people prefer to use them as garden flowers, especially if they live in woodland areas where other kinds of flowers have difficulty thriving. They can be purchased at some home garden centers and from online garden merchants.