Pinus koraiensis aka Korean Pine

Pinus koraiensis, or Korean pine, belongs to the pine family. This evergreen tree grows in Korea, northeastern China, eastern Russia, and Japan. It belongs to the white pine group and grows slowly. Garden trees reach 30–50 feet [9.1–15.2 metres] tall. Their spread can reach 35 feet [10.7 metres]. In its native range, it can exceed 100 feet [30.5 metres]. Young trees have a narrow, pointed crown with rising branches. Older trees form a wider crown with a rounded top. Their branches spread outward and often reach the ground.

The needles give the tree a blue-green look year-round. They grow in bundles of five and have blunt tips. Dark green outer faces contrast with pale lines inside. Needles stay on the tree for about three years. Gray-brown bark sheds uneven flakes, exposing red-brown bark beneath. Young shoots have a thick coat of red-brown hairs. The tree bears male and female cones on one plant. Its flowers offer little visual interest. Chicago records bloom from March to April. Brown, resin-rich cones reach 3.5–6 inches long. They grow alone or in small groups and hold edible seeds.

Grow Korean pine in full sun and well-drained soil. It can also grow in light shade. Moist loam suits it, but it accepts sand and clay. Acidic to neutral soil is preferred. Avoid wet ground that drains poorly. The tree tolerates some drought but prefers moderate moisture. Cool summers suit it better than hot, humid weather. Sources place it in USDA zones 4–7, with some zone 3 tolerance. The RHS rates its cold hardiness as H7. It needs no routine pruning.

Use it as a lone tree, in groups, or for screening. Its lasting foliage adds winter interest to a garden. It also suits bonsai and supports imperial moth larvae. Wind can damage the tree. Some sources report few major pest problems in suitable conditions. Others list needle scale, sawflies, moths, borers, aphids, and adelgids. Diseases include tip blight, rust, rot, honey fungus, and needle cast.

The large seeds supply pine nuts for commercial harvest. People eat them raw or cooked, or grind them for soups. Their oil also serves in soap and lubricants. The timber has uses in furniture and building. Needles yield dye, while bark supplies tannin. PFAF records traditional Korean medicinal uses for the seeds. These reported uses do not establish safe home treatments.