Mongolian deutzia is a small-flowered East Asian shrub. It reaches about 6.5 ft (2 m) and carries many white flowers in flat-topped clusters.
Mongolian deutzia has smaller, rounder petals in compact flat-topped clusters. Deutzia crenata has longer, narrower petals and more elongated flower clusters.
Why they get mixed upBoth are deciduous shrubs with opposite leaves and masses of white, five-petaled flowers.