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By Samantha Burbach, Director of Education & Programming – 03/18/2021

Shrubs are a great asset to the landscape, but over the years they can become unkempt and/or overgrown. To get your shrubs looking nice again, rejuvenation or renewal pruning may be in order. Both forms of pruning help to restore the vigor, size, and shape of the shrub, as well as improve flowering of flowering shrubs or improve stem color for ornamental shrubs like dogwoods or willows. Late winter to early spring is the best time for either of these types of pruning because the plants are still dormant.

Rejuvenation Pruning

Rejuvenation pruning is the act of cutting back the entire shrub to a few inches from ground level. This severe pruning will cause a flush of new growth to regenerate from the base of the plant, thus giving you a refreshed shrub with all new growth and a smaller size.  The shrub will not flower the first year but will flower more vigorously in subsequent years (2-3 years after pruning). The young new growth will also be more vibrant if you are pruning a colorful-stemmed shrub, such as red- or yellow-twigged dogwoods.

Renewal Pruning

Renewal Pruning is a slower process where one third of the shrub is pruned to the ground each year over the course of three years, until all the old wood is pruned out. By only pruning out one third of the plant in a year, you will create less stress for the plant all at once and you will still have some flowering from the mature stems/canes that remain. In the first year, choose one third of the oldest stems or canes and cut them to the ground. In the following year, choose one half of the remaining old stems/canes and cut those out, and in the third year you can remove the remaining old stems/canes. Each year, new stems/canes will begin growing from the base of the plant, and by the time you get to the third year you will be left with a smaller, more refreshed shrub. On flowering shrubs, renewal pruning can also be done after flowering so you can enjoy the floral display on the stems you are removing, however, dormant pruning promotes a flush of new growth in spring and minimizes spread of disease or insect damage to the fresh pruning wound. If you opt for renewal pruning while the plant is dormant, try forcing the branches to bloom indoors so you still get to enjoy the removed flowers. See a resource on forcing branches here: http://klehm.org/forcing-winter-branches-to-bloom/

What can be pruned using these methods?

Rejuvenation and renewal pruning will only work for multi-stemmed, deciduous (loses its leaves in the fall) shrubs. Neither method should be used on a tree or shrub with a single trunk coming from the ground or on evergreen shrubs because you will simply be cutting these down without generating new growth. Additionally, these methods may not work on shrubs that are very old with extensive woody growth and/or dead stems/canes as these may not be able to handle the stress of being cut back and generate new growth. If you have a severely overgrown shrub with mostly old, woody growth, you can try rejuvenation pruning and if the shrub doesn’t grow back, you probably would have needed to replace it anyways.

Shrubs that do well with rejuvenation pruning:

  • Red- and yellow-stemmed dogwoods
  • Forsythia
  • Witch hazel
  • Lilac
  • Weigela
  • Spiraea
  • Flowering quince
  • Butterfly bush (cut back every year for best flowering)

Shrubs that do well with renewal pruning:

  • Viburnum
  • Rhododendrons
  • Azaleas
  • Gray dogwood
  • Red- and yellow-stemmed dogwoods
  • Forsythia
  • Witch hazel
  • Weigela
  • Spiraea
  • Flowering quince

Take a look at the deciduous shrubs in your yard and garden, and if they’re looking overgrown, losing vibrant color, or haven’t been flowering well in the past few years, consider giving them a rejuvenation or renewal pruning. If you have any questions before making any cuts, check out the additional resources below or feel free to give us a call at 815-965-8146 or email sburbach@klehm.org

 

Additional resources:

Pruning deciduous shrubs by species list from The Morton Arboretum: https://www.mortonarb.org/files/Pruning%20deciduous%20shrubs%20by%20species.pdf

Purdue Extension – Pruning Ornamental Trees and Shrubs: https://www.extension.purdue.edu/extmedia/HO/HO-4-W.pdf