When Should Hydrangeas Be Exposed?

To protect your hydrangeas from spring frost, consider covering them as a defensive tactic. However, be cautious not to leave the cover on for too long and the temperatures suddenly rise, as this could overheat the plants. Pruning at the wrong time is essential, as smooth hydrangea blooms on new wood, while bigleaf hydrangeas bloom on old growth from late winter to early spring.

Learning how to prune hydrangeas is an easy gardening skill, but knowing when to prune them takes a more experienced grower. Bigleaf hydrangeas should be pruned until new growth appears in the spring, making pruning cuts one quarter inch above the first set of live buds. Stems with live buds will be green on the inside.

Hydrangeas are popular blooming woody shrubs in Minnesota landscapes, and their pruning depends on the shrub’s heading. Mophead and lacecap hydrangeas bloom satisfactorily with little attention, but annual pruning is necessary. In the spring, do not remove the mulch too fast; wait until all danger of frost has passed before uncovering to ensure beautiful blooms from old and new wood.

Climbing hydrangeas are pruned after flowering in summer, leaving the mulch on the hydrangea all winter and into the spring until the last possible frost has passed. In colder climates, wrap or completely cover marginally hardy hydrangeas, especially those that bloom on old wood.

Pruning is not essential, but if left unpruned, the plant will get taller each year, with most flowers at the top. It is recommended to cover the hydrangea when spring frosts return to keep the buds from freezing, as freezing will prevent blooming.