Pinus pumila aka Japanese Stone Pine

Pinus pumila is an evergreen shrub in the pine family. Its common names include dwarf Siberian pine and Japanese stone pine. It comes from eastern Asia, from Siberia to northern China and Japan. Its range also includes northern Korea and northern Mongolia. In China, it grows at elevations of 3,280–7,550 feet [1,000–2,300 metres]. It is not native to Britain or Ireland. The species name refers to its dwarf form.

This pine forms a low shrub, sometimes spreading along the ground. It lacks the clear main stem of an upright tree. Garden heights range from about 1–9 feet [0.3–2.74 metres]. Oregon State gives an upper height of 10 feet [3 metres]. Plants can spread to 12 feet [3.66 metres]. The dense needles grow in groups of five. Most measure about 0.13–0.23 feet [0.04–0.07 metres] long. Some reach 0.33 feet [0.1 metres]. Pale lines give the upper needle surface a blue-green look. The lower surface is dark green and lacks those lines. Small teeth line the needle edges.

As a conifer, this plant bears cones rather than true flowers. The male cones are deep red and stand out. Several female cones grow together near the ends of branches. Young seed cones have a purple to violet colour. They turn reddish brown or yellowish brown as they ripen. Cone lengths range from about 0.08–0.17 feet [0.025–0.05 metres]. The cones and blue-green foliage give the shrub distinct features. Its evergreen leaves also provide interest through winter.

Grow this pine in full sun with moist, well-drained soil. Loam suits it, but it also tolerates sand and clay. Avoid wet ground where water drains poorly. It prefers sites with cool summers. Hot, humid summers can make it hard to grow well. Missouri Botanical Garden lists USDA zones 4–7. Oregon State lists zone 5, while noting reports down to zone 1. Its water needs are moderate, and routine maintenance is low.

Use this shrub as an accent in a rock garden. It also fits shrub borders where its broad form has space. It tolerates deer and clay soil, but several pests can cause trouble. Pine needle scale can become a serious local problem. Sawflies, moths and borers may also attack it. Diseases include tip blight, rusts and rots. Poor soil and an unsuitable climate can make growth difficult.