Geranium thunbergii, commonly known as Japanese geranium or Japanese cranesbill, is a perennial herb native to grasslands, forest edges, and mountain slopes in East Asia, including Japan, Korea, and China. It typically grows to a height of 12-24 inches (30-60 cm) and spreads 18-24 inches (45-60 cm). The plant has a mounding habit with deeply lobed leaves that turn red in the fall, adding to its ornamental value. From late spring to early summer, it produces small, five-petaled pink flowers that are moderately showy. The flowers give way to distinctive beak-like seed capsules, which contribute to the common name "cranesbill".

Japanese geranium is valued for its medicinal uses, particularly as an antidiarrheic drug in Japan, and for its aesthetic appeal in gardens. It is suitable for border plantings, woodland gardens, and as ground cover. This species thrives in moist, well-drained soils rich in organic matter and prefers partial shade, although it can tolerate full sun in cooler climates. While generally low-maintenance, it may require additional water during dry periods. It is not known for serious pest or disease problems, but overwatering can lead to root rot.CC BY-SA 4.0