A website from UGA Cooperative Extension

When is the best time to prune hydrangeas? It depends on whether they are a type that blooms on old wood or on new wood. Old wood or new wood? What does that mean? If your garden has hydrangeas, then you need to know that there are distinct types of hydrangeas that are pruned differently. One type produces flower buds on “old wood” and the other type produces bloom buds on “new wood.”

Hydrangeas to illustrate the plant the article is about
Hydrangeas are a beautiful landscape plant.

What is “old and new” wood? Stems are called old wood if they have been
on the plant since the summer before the current season. New wood are stems that develop during the current season. The type most commonly found in the garden is the one that produces buds on “old wood”. This includes the old garden hydrangeas such as Mophead, Big Leaf, and Lacecap types (Hydrangea macrophylla) and the Oakleaf hydrangea (H. quercifolia). They all produce blooms on old wood.

The best time to prune old wood hydrangeas is after they have flowered and no later than August 1. If you have had problems in the past with your hydrangeas not blooming, it may be because you have pruned them at the wrong time or the frost has killed your blooms. Now is the time to prune them. September will be too late. To tidy up your hydrangea just snip off the blooms. You can do some shaping at this time by pruning to the first leaf of new growth above the node. Cut out dead wood and prune back older stalks to the soil level to promote larger, bigger blooms for next season. Because this shrub blooms on old wood, you do not want to potentially cut off any flower buds for the upcoming season, so mark your calendar to prune in July.

What about new wood bloomers? These are the hydrangeas that set flower buds on current season wood (new wood). It is easy to grow these hydrangeas because they bloom every year regardless of how they are cared for or treated. They can be pruned to the ground in the fall and they will emerge in the spring with bountiful blooms. This includes the PeeGee hydrangeas (H. paniculata) like ‘Limelight’ and the Annabelle types (H. arborescence). ‘PeeGees’ can be pruned in the fall or winter. Trim out dead and crossing stems and prune to shape the plant. It is not necessary to prune every year. Pruning this shrub helps the plant grow a strong base with upright branches that are strong enough to hold all of the large flower heads. It also encourages the plant to put more energy towards growing flowers that flourish from June to September.

Just to add to the confusion on pruning, there is one exception – “Endless Blooming.” ‘Endless Summer’ variety hydrangeas produce flowers on old and new wood. They bloom in early spring and then bloom later on new wood. This plant can continue to produce flowers all summer. Cut faded flower stems to half their length to encourage new growth and buds. Prune after last bloom by August 1 to control shape and height.

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