It grows to 1.2 m ( 4 ft ) tall by 60 cm ( 24 in ) wide .
It is a herbaceous perennial with leaves divided into many small leaflets , and panicles of lilac flowers with white stamens in summer .
Growing to 1.2 m ( 4 ft ) tall by 60 cm ( 24 in ) wide , it is a herbaceous perennial with leaves divided into many small leaflets , and panicles of lilac flowers with white stamens in summer .