‘Bailmer’ is a deciduous shrub which grows 4-6’ tall. It has mophead flowers which bloom on old wood from June-July and new wood from August through October. Flower color is dependent on the soil in which the hydrangea is planted – blue in acidic soils and rose-pink in alkaline soils – and color will change as the flowers age. It is hardy to zone 4 so will survive better than most Hydrangea macrophylla in Chicago’s harsh winters .