Privet,  Ligustrum vulgare
Oleaceae or Olive Family

Flowering branch Tall shrub, to 6 ft or higher.  Leaves oblong oval and opposite each other, about 1-2 inches long.  Flowers small, white, tubular, with widely flaring petals, in dense clusters.  Blooms in late spring to early summer. Fruits are blue berries in autumn.

Commonly cultivated hedge, occasionally escaping to roadsides and thickets.  Occasional in open thickets in the Park.

Unlikely to be confused with anything else in the Park when in flower.  When not in flower, the small opposite leaves are distinctive.