Matthiola arborescens Sternb. - Brassicaceae
perennial white stock, white tree stock 'Alba' (Matthiola arborescens var.alba), Strauch-Levkoje

Perennial plant or subshrub, frequently grown as garden plant; flowers purple or white (var.alba), fragrant.
Flower scent similar to Matthiola incana and Erysimum cheiri.

Matthiola arborescens var.alba, CC BY-SA 3.0, Author: Andreas Kraska