Water regularly, especially during the first year after planting, to establish a strong root system. Once established, Japanese Tree Lilacs are moderately drought-tolerant.

Water deeply when the top 5-7 cm of soil feels dry to the touch. Avoid overwatering, which can lead to root rot.

Prune Japanese Tree Lilacs primarily to shape the tree and remove dead, damaged, or crossing branches. The best time for structural pruning is in late winter or early spring before flowering.

Light shaping can be done after flowering to maintain desired form. Remove suckers from the base promptly.

Propagation is typically done through grafting or budding onto rootstock, often *Syringa amurensis* or *Syringa vulgaris*. Seed propagation is possible but can be slow and may not produce true-to-type plants.

Softwood cuttings can be taken in early summer and treated with rooting hormone.

Repotting is generally not applicable as this is a tree that is planted in the ground.

If grown in containers for nursery stock, repot into a larger container in spring when the plant is dormant, using well-draining potting mix. Ensure adequate drainage holes in the container to prevent waterlogging.