It is an herbaceous perennial , growing to 1 m in height , with pinnate leaves about 7 â `` 15 centimetres ( 3 â `` 6 inches ) long , with 9 â `` 17 leaflets . It is a herbaceous perennial , growing to 1 m in height , with pinnate leaves about 7 â `` 15 centimetres ( 3 â `` 6 in ) long , with 9 â `` 17 leaflets .