Syringa reticulata aka Japanese Tree Lilac

Syringa reticulata, or Japanese tree lilac, belongs to the olive family. Kew gives its range as the Russian Far East, China, and Japan. Garden sources focus on trees native to Japan. It grows as a small deciduous tree or large shrub. Garden plants reach 20–30 feet [6.1–9.1 metres] tall. Their crowns spread 15–25 feet [4.6–7.6 metres] wide. Growth is moderate, with stiff branches and a rounded crown. Plants may have one trunk or several stems.

Young bark peels and has a reddish-brown tone. Older bark turns gray and develops scales. Pale horizontal lenticels mark the bark and shiny brown stems. The simple leaves grow in opposite pairs along the branches. They have smooth edges, pointed tips, and a broad, egg-like shape. Their upper sides are dark green, with paler undersides. Fine hairs cover the leaf undersides on some descriptions. Leaves emerge early in spring and offer little fall color. Brown buds sit against the stems without stalks.

Creamy white flowers open from May into June. Large panicles can reach 1 foot [0.3 metres] long. The bloom lasts about two weeks, according to NC State. Its scent resembles privet rather than the sweeter common lilac. The flowers draw butterflies, hummingbirds, and insect pollinators. Dry capsules follow the blooms in large clusters. These change from green to yellow, then tan as they mature. Fruit clusters can stay on the tree through winter.

Full sun gives the best flower display, though plants tolerate shade. Choose rich, acidic soil that drains well. The tree also tolerates heavy clay and urban growing sites. Allow good airflow around its crown. Chicago lists USDA zones 3–7 and moderate water needs. Cool climates suit it better than warm ones. Prune just after bloom to protect next year's flower buds. Remove old flower heads after flowering. Use it near patios, along streets, or as a specimen. Small groups and large hedges are other supported uses. Its crown gives summer shade and shelter for wildlife.

This lilac has few major pest or disease problems. Sources report resistance to mildew, scale insects, and borers. Caterpillars can still cause trouble. Deer browsing is less of a concern for this tree. The supplied species sources do not establish edible uses or toxicity.