x
 
 
Learn which plants thrive in your Hardiness Zone with our new interactive map!

How to Prune Annabelle Hydrangeas

By Jacob J. Wright ; Updated September 21, 2017

Massive ball-like clusters of white flowers weight down the stems of the Annabelle hydrangea (Hydrangea arborescens "Annabelle") every summer. You cannot make a mistake in pruning this selection of hydrangea because it grows back and flowers whether you prune stems in winter, spring or summer. Pruning is done based on personal preferences: do you want a large shrub or a slightly smaller plant with the flowers?

Creating Smaller Shrubs

Severely cut back all stems of the shrub with hand pruners so that they are 4 to 6 inches tall in very early spring. Discard the stems to the compost pile.

Scatter 1 to 3 inches of fresh compost or cured manure around the the plant in a ring 2 feet in diameter. Avoid placing the compost atop the stem bases.

Allow the plants to rejuvenate in the spring and summer. This annual severe pruning creates stems that will be topped by large, rounded flowers that will arch the stems from all the weight.

Cut back all stems to a height of 18 to 24 inches Immediately after flowering ends. Allow regrowth to sprout and if the growing season is long, a lighter, second flowering may occur in September or October before the killing frosts.

Let the stems remain after the frost and across the winter. They may be cut back the following spring as in Step 1, or if your winters are particularly cold in your region, the stems will be naturally killed back to the ground and re-sprout as if they were pruned.

Creating Large Shrubs

Cut back stems to a height of 18 to 24 inches in early spring with a hand pruners. Make the pruning cuts 1/4 inch above a dormant bud or swollen knot on the stem.

Scatter 1 to 3 inches of fresh compost or cured manure around the the plant in a ring 2 feet in diameter. Avoid placing the compost atop the stem bases.

Allow the plants to rejuvenate in the spring and summer. This annual reductive pruning creates stems that will be topped by slightly smaller flower heads that will not weigh down the stems as heavily than if a severe pruning occurred as in Section 1.

Trim back stems by 10 to 18 inches after the summer flowering ends. The regrowth should not be pruned further the rest of the year so that if the growing season is long enough, a second flowering can be enjoyed in autumn.

Leave the stems across the autumn and winter and plan on conducting the next pruning, if desired, next spring based on your aesthetic and flowering preferences.

 

Things You Will Need

  • Hand pruners (secateurs)

Tips

  • Always purchase an Annabelle hydrangea while in flower so you are assured you have one with the larger, white sterile flowers as compared to the white-type smooth hydrangea with the fluffy, small fertile flowers.
  • Some gardeners place a wire cage form above the lengthening stems of Annabelle that fully re-sprout after a severe spring pruning. As the stems grow through the cage, they are supported and tend to not flop or bend as much when the massive flowers form in midsummer.

About the Author

 

Jacob J. Wright became a full-time writer in 2008, with articles appearing on various websites. He has worked professionally at gardens in Colorado, Florida, Minnesota, New York, North Carolina and Pennsylvania. Wright holds a graduate diploma in environmental horticulture from the University of Melbourne, Australia, and a Master of Science in public horticulture from the University of Delaware.