Jasminum mesnyi aka Japanese Jasmine

Jasminum mesnyi is an evergreen shrub in the olive family, Oleaceae. Its common names include primrose jasmine and Yunnan yellow jasmine. The older name Jasminum primulinum refers to the same species. Its native range runs from south-central China to Vietnam. It grows in a subtropical climate. It is not native to Britain, Ireland, or Oregon.

Long, thin stems arch out to form a broad mound. With support, the shrub can spread as a sprawling vine. Oregon State gives a garden size of 5–10 feet [1.5–3.1 metres] tall and wide. RHS gives a smaller height of 5–8 feet [1.5–2.5 metres]. Its listed spread is 3–5 feet [1–1.5 metres]. RHS places the time to full size at 10–20 years. Young stems are green and square in cross section. They turn woody with age. Glossy, dark green leaves grow in opposite pairs. Each pinnate leaf has three oval to lance-shaped leaflets.

Flowers open in winter or spring, with scattered blooms at other times. Each flower grows alone on a short stalk. The pale to lemon-yellow blooms reach about 1.6 inches across. Many are semi-double, with six to ten petals. Reports differ on whether the flowers have a scent. The fruit is a small, oval, blackish-purple berry. Each part contains one or two seeds. The supplied sources do not establish edibility or toxicity.

Grow it in sun or partial shade with good drainage. It tolerates shade, but flowers less there. RHS lists chalk, loam, and sand as suitable soils. It accepts acid, neutral, and alkaline conditions. Choose a sheltered site for outdoor planting. RHS recommends a frost-free spot and assigns UK hardiness H3. Oregon State lists USDA zone 8, with zone 7 in parentheses. Under glass, use peat-free, loam-based compost and bright, filtered light.

This shrub suits patios and containers where space allows. Its arching growth works well where stems can spill downward. Occasional hard pruning helps keep the mass of stems tidy. Propagate it from semi-hardwood cuttings or by layering in autumn. Aphids, scale insects, and mealybugs may attack it. Under glass, red spider mites can also cause trouble. Honey fungus is a rare disease risk.