These macrophylla / paniculata Hydrangeas are sold as 'Lost Label'. The Hydrangeas are reduced to clear,  the growers pots may also be slightly damaged on arrival. 

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This shrub is deciduous, it ill lose all of its leaves in autumn, fresh new growth will appear in the spring.

Do not cut the faded flower heads back until spring. In spring, you should cut back the faded flower heads to a healthy pair of buds. Remove any misplaced or diseased stems.