This grower is sure of this plant identification.
Filipendula rubra 'Venusta' Flowers from June-August and is best in a moist to wet soil in a sunny position. HxS 1.5mx1.5m
'Queen of the Prairie' from N. America and a superb plant in the right place. Dark green leaves with plumes of the deepest pink opening from dark pink buds. Needs moist soil to do well and enjoys boggy conditions. RHS Award of Garden Merit.
'Queen of the Prairie'
Filipendula rubra ‘Venusta’ ('Queen of the Prairie' ). ‘Venusta’ has large corymbs of deep pink flowers in summer, which age to paler pink. Leaves are bright green.