I can't say if it is timed exaclty with ROS, but its definitely on the late side of the season.

Lespedeza thunbergii ‘Gibraltor' A glowing deep lavender
selection to 5', zone 5. Usually killed back to the ground in winter in
zone 5, but regrows with great vigor into a graceful, fountain-shaped
shrub. Blooms profusely in late summer at a time when color in the
border is much appreciated. Grow in full sun, in ordinary, well
drained soil.