When should hydrangeas be pruned?

Ugh! This is always tricky because there are different types of Hydrangeas and when to prune them depends on the type.

In Minnesota right now our hydrangeas are in bloom. Depending on the type some might be fading out, and some might be in their full glory! You can cut off the flower heads on these hydrangeas and bring them inside, use for fall décor or save them to put in outdoor winter arrangements. Cutting off the flowers for use is different than pruning hydrangeas. So, cut away at those blooms if you want, but don’t prune your hydrangeas until you’ve read below!

“Never” is not an acceptable answer for when to prune but if you don’t know what kind of hydrangea you own, a better answer might be waiting a full season to determine whether you have an old or new wood blooming hydrangea.

The most popular hydrangeas we see in Minnesota gardens are Arborescens: Annabelle, Incrediball, and Invincible Spirit.  They can be trimmed in spring or fall.

Paniculata: Lime Light, Strawberry Sundae, Quick Fire, Bobo, Pee Gee, Pink Diamond, and Pinky Winky, can also be trimmed in spring or fall.

Macrophylla: Blooms are pink, purple or blue. Many often times called Endless Summer. These hydrangeas bloom on OLD WOOD. This means that each year they produce blooms off the wood from the current year. DO NOT cut these hydrangeas after July. In August they start to set blooms for the next year.

What is the difference between an old wood and new wood bloomer.  Well, old wood is merely last year’s stems, so hydrangeas that bloom on old wood set their flowers in late summer on stalks from the previous year.  Typically,these are mophead, bigleaf, lace cap, and oakleaf varieties.

These shrubs require very little pruning, but if you must, here are some tips:

• Right after flowering, (no later than July) trim stems to a pair of healthy buds.
• In late winter or early spring, cut out weak or damaged stems to ground level; but don’t prune more than 1/3 of the oldest stalks.
• This can be done every summer to maintain their shape and keep them

What about new wood bloomers?  This variety of hydrangea set their blooms on the current season’s new wood.  These include the smooth panicle and limelight varieties.

Tips for pruning new wood shrubs:

• Cut off faded flowers in late summer for a prettier hydrangea.
• Prune out the oldest wood to keep the shrub vital.
• Cut back the entire shrub in late winter before new growth begins.

Don’t be frightened to prune your hydrangeas. If you’ve trimmed at the wrong time and don’t get any blooms, you’ve learned a lesson.  Your hydrangea will survive and will bloom next year!