Pinus densiflora aka Japanese Pine

Pinus densiflora, or Japanese red pine, is an evergreen conifer. It belongs to the pine family, Pinaceae. Its native range spans the southern Russian Far East and Korea. It also grows in central and southern Japan. This tree comes from temperate parts of eastern Asia. Garden trees reach about 40–60 feet (12–18 m) tall and wide. Some wild trees reach 100–130 feet (30–40 m). Sources differ on its size, with RHS giving a narrower spread.

The crown starts broad and becomes flatter with age. Long branches spread sideways, giving the tree an open shape. The trunk may lean, twist, or divide into several stems. Young shoots are smooth and green before their bark turns reddish. Thin flakes peel from the orange-red bark. Older bark near the trunk base turns gray and cracks. This mix of bark colors remains visible through the year.

Green needles grow in pairs and form tufts near shoot ends. They measure about 3–5 inches (0.08–0.13 m) long. UConn describes them as soft, twisted, and finely toothed. RHS describes them as stiff. Needles can stay on the tree for three years. The tree bears male and female cones on one plant. Its flowers offer little value for garden display. Brown to yellow-brown cones grow alone or in groups. They reach about 1.5–2 inches (0.04–0.05 m) long. Some stay on the tree for two years.

Grow this pine in full sun and well-drained soil. Several sources favor acid soil, while RHS accepts all pH levels. RHS also lists clay, chalk, loam, and sand as suitable. The tree tolerates drought but can grow in moist soil. NC State lists USDA zones 3–7; RHS rates it H7. Sources describe its growth as slow to moderate. Full size may take 20–50 years. It needs no routine pruning, and seed provides a way to propagate it.

Gardeners use it as a specimen, accent tree, or bonsai. Its form suits Japanese gardens, while evergreen needles give winter interest. It resists deer and hosts imperial moth larvae. Wind can damage it, and road salt can cause problems. Possible pests include aphids, adelgids, pine sawflies, and pine shoot moths. Honey fungus and needle cast can also affect it.