Lilac/Syringa vulgaris

Syringa vulgaris (lilac or common lilac) is a species of flowering plant in the olive family Oleaceae, native to the Balkan Peninsula, where it grows on rocky hills.Grown for its scented purple flowers in spring, this large shrub or small tree is widely cultivated and has been naturalized in parts of Europe and North America. It is not regarded as an aggressive species, found in the wild in widely scattered sites, usually in the vicinity of past or present human habitations. from Wikipedia, more information here