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Solving The Mystery Of When To Prune Hydrangeas

prune hydrangeas kansas city

Wouldn’t it be great if you could stop wondering when your hydrangeas need to be pruned? This is our most commonly asked question pertaining to plants. That’s because the answer isn’t always simple. Ahhh, don’t you just love plants?!

The first step in determining your plan of action for pruning hydrangeas is to identify what type of hydrangea you have.

Mop Head Types (Hydrangea macrophylla)

Generally pink or blue with large, thick leaves. (Single blooming and reblooming)

Mop Head Types

Lace Cap Types (Hydrangea serrata)

Can be pink, blue, purple, or white with a delicate bloom and serrated leaves. (Single blooming and reblooming)

Lace Cap Types

Oakleaf Types (Hydrangea quercifolia)

Cone-shaped blooms with large leaves resembling oak leaves. Turns red in the fall.

Oakleaf Types

Annabelle Types (Hydrangea arborescens)

White, large, dome-shaped blooms

prune hydrangeas kansas city

Limelight Types (Hydrangea paniculata)

Cone-shaped white/green blooms with a pointed oblong leaf.

Limelight Types

Once you’ve identified the type, it will fit into one of the following three categories:

  1. Mop Head types and Lace Cap types (Hydrangea macrophylla), and Oakleaf Hydrangeas (Hydrangea quercifolia)
  2. Reblooming Mop Heads and Lace Caps such as the Endless Summer line. These bloom multiple times per season. (These are called remontant Hydrangeas because they generate new blooms on current year growth.)
  3. Annabelle types (Hydrangea arborescens) and Limelight types (Hydrangea paniculata)

Category 1: Mop Heads and Lace Caps (Non-reblooming)

Prune in summer prior to fall. This type of hydrangea blooms on the prior year’s growth. This means that pruning late in the year could risk cutting off the flower buds for the next year.)

Category 2: Reblooming Mop Heads and Lace Caps (Remontant)

Pruning can occur in spring, summer, or fall because these hydrangea generate new buds throughout the growing season.

Category 3: Smooth Hydrangea (Annabelle Types) and Panicle Hydrangea (Limelight Types)

Both of these types of hydrangea bloom on current year growth, so they can be pruned just about any time. For maximum bloom, don’t prune right before they are preparing to bloom. This means late spring for Smooth Hydrangeas and summer for Panicle Hydrangeas. The High Prairie recommendation is to prune Smooth Hydrangea and Panicle Hydrangea in late fall or early spring before they break dormancy. A hard pruning will keep them neater and more compact in appearance. This can cause the stems to be weak for holding up blooms, so prune selectively.

Floppy Panicle Hydrangeas?

Below is an example of panicle hydrangeas (Limelight Hydranges), that were not pruned for the season. These hydrangeas need a hard pruning back to 18-30” in winter to early spring in order to help prevent flopping.

prune hydrangeas kansas city

Exceptions

  • Prune out dead wood at any time
  • Remove spent blooms (dead head), at any time.
  • A revitalization pruning can take place during the summer where old stems can be selectively cut to the ground. (This applies only to hydrangeas that have been in the garden five or more years) Don’t take more than one-third of the plant.

If you need help from the professionals on when to trim your Hydrangeas or other plants, give High Prairie Landscape Group a call today!