Syringa microphylla 'Palibin'
microphylla is a bushy, spreading medium-sized deciduous shrub with small, dark green, broadly ovate leaves. 'Palibin has pink flowers in loose panicles. The leaves are much smaller, and the plant itself is less vigorous growing than your more commonly planted our Syringa 'vulgaris.'
RHS pruning group: 1 or 2