Genpei-kusagi | A Fascinating Ornamental Plant Bearing the Colors of Red and White

Genpei-kusagi (Clerodendrum thomsoniae) is a tropical plant characterized by its white calyces and vivid red flowers. With its unique appearance and long blooming season, it has become popular as a garden or potted plant.

In this article, I will introduce the basic information, cultural and historical background, and cultivation tips for Genpei-kusagi.

Basic Information

• Scientific name: Clerodendrum thomsoniae
• Family: Lamiaceae
• Origin: West Africa
• Appearance: Genpei-kusagi is a climbing evergreen that grows to about 2–4 meters in height. Its small red flowers, emerging from white calyces, are striking despite their size. The leaves are glossy, deep green, and ovate in shape.
• Blooming season: From May to October, the plant can be enjoyed for a long period.

Cultural Significance

In Japan, Genpei-kusagi is cherished as a flower symbolizing the cultural and historical memory of the Genpei War.

Its striking red-and-white contrast resembles the colors of the Genji and Heike battle flags, which gave rise to the Japanese name “Genpei-kusagi.”

In its native West Africa, the plant is used in gardens and hedges, while the flowers are seen as symbols of happiness and blessing, often decorating festive occasions.

In Europe, it spread as an ornamental plant, fascinating gardeners with its exotic beauty.

Historical Background

Genpei-kusagi was introduced to Europe in the 19th century. In England, it became well known during the Victorian era, when tropical plants were widely collected and cultivated in greenhouses.

In Japan, it was brought in during the Meiji period. Its name was inspired by the red-and-white flowers, reminiscent of the banners of the Genpei War.

Within Japanese garden culture, it has been appreciated as a plant with a narrative quality, evoking a sense of history.

Gardening Advice

As a climbing plant, Genpei-kusagi thrives when supported by stakes or trellises. Here are some key cultivation tips:

Sunlight

Prefers bright locations, but in intense direct sunlight, partial shade helps prevent leaf burn.

Watering

Water thoroughly when the surface soil dries. Avoid overwatering, and reduce watering in winter.

Soil

Favors fertile, well-drained soil. Mixing perlite into commercial potting soil is effective.

Fertilizer

Apply liquid fertilizer once or twice a month during the growing season to encourage blooming. Withhold fertilization during dormancy.

Pruning

After flowering, prune unnecessary branches to shape the plant. In winter, thin out old branches to improve ventilation.

Overwintering

Sensitive to cold. Move indoors in winter or provide frost protection. A minimum temperature above 5°C is ideal.

Conclusion

Genpei-kusagi is a tropical plant admired for the beautiful contrast between its white calyces and vivid red flowers.

In Japan, it has been given a special name inspired by the Genpei War, and it is cherished along with its historical associations. It is relatively easy to cultivate, and by using stakes or trellises, I can enjoy its climbing habit both in gardens and pots.

As an ornamental plant, it offers long-lasting blossoms and makes a charming addition to any green space.