How to Propagate Thunberg spiraea?
Propagate by softwood or semi-ripe cuttings in spring to late summer or hardwood cuttings in winter

Thunberg spiraea · Spiraea thunbergii
Grow in moist but well-drained soil in full sun or light shade. Especially suitable for mixed borders
Propagate by softwood or semi-ripe cuttings in spring to late summer or hardwood cuttings in winter