Summer Pruning of Shrubs & Trees

In July we had the opportunity to attend a summer pruning workshop in Seattle coordinated by the UW Botanic Gardens as part of their professional horticulture education series.  Two of our maintenance leads, Phillip and Ray, were in attendance.

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Phillip and Ray listen as an arborist discusses what factors to consider when selecting a tree’s leader.

This outdoor demonstration class was taught by professional horticulturists and arborists on staff for the Washington Park Arboretum along with Bess Bronstein, an instructor for the Edmonds Community College horticulture program since 1989. If you love learning about plants and are interested in taking a horticulture class, Bess Bronstein is a fantastic instructor to learn from. She delivers information with wit and humor and knows how to keep a class engaged.

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We learned how they train the wisteria vines on site and how to achieve more flowering.

So what exactly should you prune?

  • Remove the 3-D’s: dead, damaged and diseased branches.
  • Remove undesirable growth (the 4th D- deranged!): rootstock suckers, water sprouts, plants prone to suckering regrowth, etc.
  • Prune bleeders. Some genera tend to bleed sap during dormancy, so summer pruning is neater. Bleeders include: maples, dogwoods, birches and beechers.
  • Prune plants prone to fungal diseases: Prunus species of trees (flowering plums and cherries), maples and dogwoods are prone to fungal disease spread if pruned during wet winters.
  • Fine prune thin small branches/leaves of Japanese maples to enhance branch view.
  • Hedge broadleaved evergreens to allow some regrowth prior to low temperatures returning.

And why prune in the summer? Pruning during the summer months is somewhat of a no-brainer considering the long stretches of dry weather we experience. Besides keeping dry, listed below are other benefits of summer pruning.

  • You can see where it’s dark and where a plant won’t flower, allowing you to make informed decisions about how to allow more light to filter in.
  • By mid-July top growth is essentially finished.  The bulk of growth has been done, but plants haven’t started storing food yet. The optimal time to prune is between mid-July and mid-August.
  • If you prune after mid-August, you risk stimulating new growth at the same time plants are trying to store food, and this can be stressful for the plant.
  • Summer pruning results in a “stunting” or “dwarfing” growth response – great for size management.
  • It’s an opportune time to manage temporary branches and emerging competing leaders.
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Ray looks at the effects of Cherry bark tortix, a moth whose larvae can kill cherry trees and infest woody trees and shrubs.

Continuing education is incredibly important to us.  It allows our employees to grow their knowledge about their field, and this knowledge is then directly applied to our maintenance clients’ sites.

To learn more about the UW Botanic Gardens continuing education horticulture workshops, click here.

Thanks for reading our blog.  Northwest Construction & Landscape, LLC is a Kitsap County landscaping company that offers landscaping, decorative concrete and lawn maintenance services to homes and businesses across Kitsap and Pierce counties.