Salvia japonica aka East Asian Sage

Salvia japonica belongs to the mint family, Lamiaceae. Its native range covers southern China and temperate eastern Asia. Kew places it in a subtropical climate zone. In central and southern Japan, it grows in woods and thickets. These sites lie in hills and mountains. It is not native to Britain or Ireland. The RHS lists Salvia chinensis as a synonym.

Sources differ on its life cycle. Plants For A Future describes it as a perennial. Kew records it as an annual. The reported height is about 2.6 feet (0.8 metres). Its listed spread is much greater than its height. That figure needs confirmation before use in garden planning. The supplied species evidence gives no details of leaf shape or stem form. It also lacks flower colour and fruit details. Plants For A Future records flowers from August to September. Each flower has both male and female organs.

Choose a sunny site with soil that drains well. Plants For A Future also lists light shade as suitable. It favours light, sandy soil, though loam is also suitable. Rich soil is preferred, but drainage remains important. The plant accepts mildly acid, neutral, and mildly alkaline soil. It can grow in dry or moist ground. A sunny woodland edge or dappled shade suits its listed garden uses. Too much winter moisture can kill plants. The source gives cold tolerance of about 14–23°F, or −10 to −5°C. It lists USDA zones 7–10, but warns against colder sites.

Sow seed under glass in March or April. Germination takes about two weeks, according to Plants For A Future. Move seedlings into their own pots once large enough. Plant them outdoors in early summer. Near the plant's cold limit, protect seedlings through their first winter. Set them out in late spring the next year. Half-ripe cuttings offer another means of propagation during growth.

The leaves serve as a flavouring in place of sage. Children also suck the flowers, perhaps for their nectar. Plants For A Future gives the plant a low food-use rating. It reports no known hazards, but this does not establish pet safety. The plant also yields a black dye. The source suggests the flowers may provide it. No medicinal uses are recorded. No species-specific pest or disease details appear in the supplied evidence.