Hydrangeas bloom at different times depending on where you live and the variety of hydrangea you grow. In general, hydrangeas bloom from late spring to summer, with some varieties blooming earlier, later or longer.
Smooth hydrangeas, or Hydrangea arborescens, bloom in June and July (early summer). Cultivars of Hydrangea arborescens include Annabelle, Incrediball and Invincibelle Spirit.
Bigleaf hydrangeas, or Hydrangea macrophylla, have numerous cultivars and bloom in the summer months of June, July and August. Endless Summer cultivars bloom continuously throughout the summer. Bigleaf hydrangeas include mophead and lacecap types, as well as variegated and all-pink varieties.
Oakleaf hydrangeas (Hydrangea quercifolia) bloom in early to midsummer. Many Oakleaf cultivars have white flowers, and some even have yellow or red foliage, adding late-summer interest to the garden.
Hydrangea paniculata, better known as Panicle hydrangeas, bloom in the summer months of June and July. Panicle hydrangeas, unlike other varieties, bloom on new growth, so pruning in spring encourages new growth and more blossoms.