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How to Prune Rhododendrons After Blooming

By Caroline West ; Updated September 21, 2017

A glorious sight in spring is a rhododendron holding its clusters (trusses) of flowers aloft. Would you like to guarantee a big annual show of blooms? Learn a simple trick to help the rhododendron produce more flowers. Many rhododendron growers think that the shrubs need no pruning, but a few interventions can take a rhododendron from ordinary to superb. Once the flowering is finished, different pruning techniques can increase the number of trusses that bloom each year, making the rhododendron bushier or dramatically revising the shape of the shrub.

Deadhead the spent trusses to increase blooms in the next year. If not removed, the trusses will set seed and energy will be wasted that could go into flower production. Take the base of the truss stem between the thumb and forefinger. Quickly and cleanly snap the stem, making sure not to damage the emerging bud beneath it. Discard it in a yard waste container.

Pinch off the leaf bud at the end of a rhododendron branch to stimulate growth to the sides. Repeat for all branches that you want to bulk up. Dispose of the pinched-off leaf buds in a yard waste container.

Clip or lop off any broken or dead branches. Perform this task as soon as the damage is noticed and at any time of the year. Cut off small and mature branches that are more than 1/2-half inch in diameter.

Clip or lop to shape the outline of the shrub. Many rhododendrons have long branches that produce few trusses. This rangy habit with its rather wild appearance is not attractive to all gardeners. The habit can be managed to some extent by pruning. Remove healthy branches that deviate from the desired silhouette.

 

Things You Will Need

  • Gardening gloves
  • Clean and sharpened pruners or clippers
  • Clean and sharpened loppers
  • Yard waste container

Tips

  • Compost all the spent trusses and leaf buds.
  • Shaping a rhododendron by pruning healthy branches can be done during the bloom period and the flowering branches can be displayed in tall vases indoors.
  • Check the habit of the variety when purchasing a rhododendron to ensure satisfaction with its overall appearance.

Warnings

  • Prune rhododendrons after flowering, in the early summer or again in early fall for best results. Pruning too close to winter will promote tender growth that is vulnerable to the cold weather.
  • Protect your hands from the stickiness on the blossom stems by wearing gardening gloves.

About the Author

 

Caroline West is a garden writer specializing in organic gardening, bulbs, and landscape design. When she's not tending her drought-tolerant, deer-resistant garden, she writes about gardening for online magazines and her local newspaper. West is also working toward a certificate in horticulture.