Pruning – It’s Worth Your Time

By Stacey Hirvela, Proven Winners
Photographs Courtesy of Proven Winners

What’s the secret of transitioning from a competent gardener to a confident one? Understanding pruning. Though this garden task strikes fear into the hearts of many, it is actually a simple and rewarding process. All you need to do to master it is to understand a few basic principles of pruning. If you take the time to prune, you will see a healthier, more floriferous garden that same season.

The Science Behind Pruning

To really understand why pruning is necessary, you need to know what pruning does to a plant physiologically. Plants are genetically programmed for apical dominance. That’s a botanical term that describes the simple phenomenon that plants always want to grow upward. Apical dominance is enforced by the terminal bud – the bud at the end of each stem - which produces a constant supply of hormones that keep the buds below it from growing. When that terminal bud is removed, production of those suppressive hormones ceases, and the lower buds are released. As a result, pruning stimulates a lot of new growth, as multiple buds take over the job that just one single bud was doing previously.

Benefits of Pruning

For the gardener, the new growth that results from pruning can result in any of the following things, depending on the kind of plant:

• More flowers. Instead of just the terminal bud producing flowers, all of the lower buds will flower as well, multiplying the effect substantially.  This is especially true for plants that flower later in the season.
• Rebloom. Reblooming plants like Bloomerang® Lilac and Bloom-A-Thon® Azaleas flower more the second time around based on how much new growth they put on after their first bloom. A light trim after they’ve finished their spring bloom means a better show come summer!
  Photo: Bloomerang® Lilac

• Better leaf color. Many plants with variegated or colorful foliage, like 'Summer Skies' Butterfly Bush or My Monet® ‘Sunset’ Weigela, display their best color and pattern on young growth. Pruning keeps their foliage vivid and showy.
• Brighter stem color. Plants with attractive stems, like Arctic Fire™ and Arctic Sun™ Dogwood, display their brightest coloration when they are younger than three years old. Pruning out older stems encourages the fresh new growth that makes these plants so popular in our gardens, especially in winter. Photo: Arctic Fire™ Dogwood

The Practical Side of Pruning

In addition to getting better flower and foliage color on your shrubs by pruning, there are some practical reasons to prune, including:

• To neaten the plant’s appearance. Some plants which bloom on new wood like ‘Limelight’ Hydrangea and Incrediball® Hydrangea hold last year’s flowers on their stems through the winter. These old flowers can be cut off in spring to keep the new growth and the current season’s flowers looking crisp and clean. Photo: Incrediball Hydrangea in winter
• To control the plant’s height and/or spread. A plant that is really too large for its space may need to be pruned into a more manageable size. Some plants, like Sunshine Blue® Caryopteris and Black Lace™ Elderberry, are capable of growing rather large, but you may want to use them in a flower bed or a smaller landscape. That will require some pruning to keep them tight and compact. Photo: Black Lace Elderberry
• To rejuvenate an old or overgrown shrub. If you’ve got a very large, old multi-stemmed shrub like Show Off® Forsythia on your property, you can give it a new lease on life by cutting it back to short stubs in spring.
• To remove dead, diseased, or damaged wood. Sometimes branches of shrubs die from weather or old age, or are damaged from animal browsing. Pruning is the best way to correct these issues.

There are many good reasons to prune shrubs but it’s important to know that pruning is not strictly necessary. No plant dies from a lack of pruning, but plenty die from being pruned improperly. There are plenty of reasons not to prune shrubs too. For example, if you are happy with a shrub’s size, looks, and performance, there is no need to prune it. If it is a dwarf variety, like Lo & Behold® Butterfly Bush or Show Off™ Sugar Baby Forsythia, it will require little to no regular pruning.

You should never prune without a reason. Every other pruning decision you’ll make, like when to prune and how much, will come back to the reason you’ve decided to prune in the first place. If you start with a good reason, you will always know what pruning needs to be done next. 

Bio: A graduate of the School of Professional Horticulture at the New York Botanical Garden, Stacey Hirvela has worked as a Manhattan rooftop gardener and as the horticulturist for Tavern on the Green restaurant in Central Park. For six years, she worked as a garden editor at Martha Stewart Living magazine where she created, wrote, and edited garden content and co-hosted a call-in radio program. Stacey is currently a member of the Proven Winners ColorChoice Shrubs marketing team, a popular speaker, and author of the book Edible Spots and Pots (Rodale, 2014).Patent Info: Pink Home Run® Rosa PP22856; Bloomerang® Purple Syringa PP20575 CPBR4071; Bloom-A-Thon® Rhododendron; 'Summer Skies' Buddleia PP22465 CPBR4657; My Monet® 'Sunset' Weigela florida PP23212 CPBR4691; Arctic Fire™ Cornus stolonifera PP18523; Arctic Sun™ Cornus sanguinea PP19892 CPBRAF; 'Limelight' Hydrangea paniculata PP12874 CPBR2319; Incrediball® Hydrangea arborescens PP20571 CPBR4166; Sunshine Blue® Caryopteris incana PPAF CPBR2316; Black Lace™ Sambucus nigra  PP15575 CPBR2633; Lo & Behold® 'Lilac Chip' Buddleia PP24016 CPBR4663; Show Off™ Sugar Baby Forsythia PPAF

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