Lithocarpus edulis aka Japanese Stone Oak

Lithocarpus edulis is an evergreen tree in the Fagaceae family. It comes from central and southern Japan and the Nansei Islands. Its native range includes Honshu, Shikoku, Kyushu and the Ryukyu Islands. Kew places it in the subtropical climate zone. The name Pasania edulis is a synonym. It can grow as a tree or a broad, bushy shrub.

The RHS gives a garden height range of 26–39 feet [8–12 metres]. Its descriptive account gives a lower height of 30 feet [9 metres]. The spread can reach 13–26 feet [4–8 metres]. Plants take 20–50 years to reach their full size. The leaves stay on the plant year-round. They feel leathery and have a narrow, oval shape. Each leaf narrows toward both its tip and base. Leaves reach about 0.49 feet [0.15 metres] in length. Their upper sides are yellow-green, while their undersides are dull green.

Flowers appear in spring on short spikes that stand upright. These spikes reach about 0.23 feet [0.07 metres] long. Acorns may follow the flowers, but they develop over two seasons. Full-grown acorns can reach about 0.08 feet [0.025 metres] long. The slow fruit cycle means acorns need more than one season to reach full size.

Grow this species in sun or partial shade. It accepts clay, loam and sandy soils. Choose acid or neutral soil that drains well. The RHS lists both moist, well-drained soil and well-drained soil. Give it shelter from cold winds that dry the leaves. This matters in places where frost occurs. The RHS rates its UK hardiness as H5. Plants For A Future lists USDA zones 6–9. Garden uses include woodland canopy planting and planting for bold form. Its evergreen leaves and broad habit provide lasting structure.

The RHS lists few usual pest or disease problems. It also includes this species among low-maintenance planting choices. Plants can be raised from seed or semi-hardwood cuttings. Plants For A Future lists the seeds as edible, raw or cooked. It gives them a low food rating because they taste poor. Tannins may account for some of that taste. Soaking for several days, with fresh water changes, can remove tannins. Grinding the seeds before soaking can shorten this process. The same source reports no known hazards, medicinal uses or other uses. That hazard report does not establish safety for pets.