Thuja koraiensis, commonly known as Korean Arborvitae, is an evergreen tree native to mountain forests and valleys in Korea and parts of northeastern China. It typically grows to a height of 3–10 meters. Korean Arborvitae has a conical to broadly pyramidal shape with dense, flat sprays of foliage. The scale-like leaves are 2–4 mm long, extending up to 15 mm on vigorous shoots, matte dark green on the upper side, and feature broad, vivid white stomatal bands on the underside. The cones are distinctive, starting as oval, yellow-green, and ripening to red-brown, measuring 7–11 mm in length and 4–5 mm in width, opening to 6–9 mm broad with 8-12 overlapping scales.

This species is valued for its ornamental foliage, which provides a striking contrast between the green upper and bright white lower sides. It is suitable for use as a specimen tree, in privacy screens, or as part of a conifer collection. Korean Arborvitae requires moderate watering and thrives in well-drained soils, tolerating both full sun and partial shade. While it is not commonly found in cultivation due to seed scarcity, it is a low-maintenance choice for gardeners who can obtain it.CC BY-SA 4.0