pruning

[Reviewed and updated on January 3, 2019]

One of my favorite gardening activities is pruning. I admit that I am addicted to it. I like to observe the way plants respond to pruning with new growth and I love to spend time ‘grooming’ my plants.

I should start this pruning post with a disclaimer: I primarily prune to improve the health and vigor of a plant. I’m not into what some call ‘aesthetic pruning.’ My pruning style is more ‘natural’ than others as I am attracted to a more naturalized way of gardening. I tend to let things grow to their maximize size and into their natural habit.

However, there are a few things that I can’t stand such as branches touching the ground, inward growth, or rubbing stems. I also look for foliage that has become too dense for good air circulation or light penetration. I am also looking to remove any potentially concerning disease or pest issues.

This article covers what I consider to be basic homeowner pruning or ‘on the ground pruning’ as in feet don’t leave the ground. In cases of large trees, potential hazards to property, or anything that feels unsafe or beyond your comfort zone I always recommend contacting a certified arborist via ISA treesaregood.org or certified horticulturist via your state nursery and landscape association. Resources for more specialized pruning topics are provided below as well.

So what is pruning?

Pruning is simply the removal of selected parts of plants such as stems, branches, flower buds, etc. In my opinion ‘proper pruning’ includes pruning that improves the health and vigor of a plant, promotes flowering, and naturally shapes a plant for visual appeal.  I generally do not encourage pruning to control size (right plant, right place) and I do not advocate shearing woody ornamental shrubs into squares, meatballs, or triangles.

Basically there are four types of pruning.

  1. Shaping that enhances the natural habit.
  2. Thinning to create a healthier plant (especially very dense stemmed shrubs) by allowing more air circulation and sunlight into the base as well as removal of rubbing branches and root sucker growth.
  3. Reducing which is to control the size when necessary.
  4. Rejuvenating to encourage new growth, vigor and flowering of an older shrub by removing about 1/3 of the oldest wood.

Sometimes immediate pruning is necessary due to obstruction of a path, the plants have dead, diseased or pest infested parts, or there may be other safety issues such as with large trees.

Before you prune

  • Know your subject. Identify the plant to understand its natural habit and size as well as flower season. Some plants bloom on old wood vs. new wood for instance.
  • Take your time. I admit that sometimes I will study a subject for more than a year before I decide if I’m going to take action or not. And I don’t want to remove too much at once which can cause stress.
  • Make observations. You can observe previous cuts and see what kind of growth reaction occurred from those.
  • Be proper. Use the proper tools for your task. Knowing when a pruning saw is better than loppers or hand pruners is important. My favorite tool I keep in my bag is a hand-held bypass pruner because they make a cleaner, sharper cut. I personally don’t care for anvil pruners as they seem to crush stems to me. I also love my folding pruning saw over loppers which just always feel awkward to me. I am also pretty good with a pole pruner, again because my feet don’t leave the ground.
  • Start clean and sharp. Make sure your tools are in good condition and are clean. I can’t stress enough how important it is to keep you tools clean. Disinfecting and sterilizing your tools prevents the spread of disease-causing pathogens. I usually perform a good cleaning and sharpening to all my pruning tools before I begin my winter pruning. I also keep alcohol wipes in my garden bag between pruning subjects.
  • Know your goal. Begin with knowing why you are pruning and proceed accordingly: shape, thin, reduce or rejuvenate.

The most common question I get is when is the right time to prune?

Everyone has heard the “when the pruners are handy” response.  But the answer really depends on what you are pruning. However, these are the seasonal guidelines that I have learned to follow:

Winter in general is the best time to prune when plants are dormant, especially to rejuvenate or create new growth. It is my favorite time to prune deciduous plants that loose their leaves because I can better see the structure of the plant and find potential issues such as rubbing stems.

In the spring it is best to prune before plants come out of dormancy or ‘bud break’ or even better yet wait until growth has flushed out. Pruning at bud break can stress a plant and actually set back the plants growth and cause other problems as well.  Generally speaking, after flowering is a good time to prune to avoid cutting off potential flower buds. Most spring blooming plants set flower buds on the current summer growth for the following Spring. These plants are referred to as blooming on ‘old wood’ because buds are set on last year’s growth.  Plants that flower after mid-June by and large produce flower buds on ‘new wood’ or the current season’s growth.

Summer is a good time to thin and shape plants as needed. Pruning in late summer (no later than Labor Day in my zone 7 is my general rule) can minimize water sprouts and suckering for plants prone to that reaction.

Pruning in the fall should be avoided as plants need time to go into dormancy and harden off for winter. Pruning creates the opposite reaction and surges the plant into new succulent growth, which will be killed with frost and potentially harm the plant as well.

Beware of bad pruning practices

Don’t assume because you see something being done in a landscape that it is the correct thing to do. Unfortunately there are untrained landscapers (versus certified arborist and horticulturist) and homeowners that perform bad pruning jobs. Here’s a few to avoid:

  • Topping or the indiscriminate removal of the top portion of a tree creates starvation, stress, invites pest and disease problems, and produces weak limbs and sprouts.  It’s also ugly and will lead to the demise of the tree.
  • Tipping or the removal of only the ends of branches which creates stress on the plant, promotes more growth on the ends of the branches, and invites pest and disease issues also ultimately leading to the demise of the plant.
  • Lions-tailing is a practice where a tree is overly thinned of its inner branches and results in a look that is unnatural and the practice is also detrimental to the health of the tree.
  • Crepe Murder is a form of topping specific to crepe myrtles that has become rampant thanks to the assumption that if you see it in a landscape you should do it too. Please don’t.

I have put together a Pinterest board on pruning for some visual tips. Below are a collection of resources on general as well as specific pruning topics such as roses, hydrangeas, fruit trees, evergreens and more.

Happy Pruning!

Resources for Common Pruning Topics

Pruning (General)

Arbor Day Foundation: Keys to Good Pruning

ISA Trees Are Good: Pruning Trees

University of Minnesota Extension: Pruning Trees and Shrubs

Texas A&M Extension Earth Kind Landscaping: Follow Proper Pruning Techniques

Cornell University Cooperative Extension: An Illustrated Guide to Pruning Ornamental Trees and Shrubs (30 page pdf)

University of Florida Extension: Restore a lions-tailed tree

PennState Extension: Pruning Landscape Trees

Virginia Cooperative Extension: A Guide to Pruning / Stop Topping Trees

Virginia Cooperative Extension: A Guide to Successful Pruning, Pruning Shrubs

UGA Cooperative Extension: Basic Principles of Pruning Woody Plants 

State-by-State Gardening: Pruning Tips to Salvage an Overgrown Landscape

Pruning Evergreens

Virginia Cooperative Extension: A Guide to Successful Pruning Evergreen Trees

Pruning Roses

University of Illinois: Rose Pruning

NC State University Extension: Pruning Knock Out Roses

UGA Extension: Pruning Roses

Pruning Hydrangeas

UCCE Master Gardeners: When Should I Prune My Hydrangea

Hydrangeas in the North: Getting Blooms in Cold Climates

Virginia Cooperative Extension: Hydrangea Selection, Pruning & Care

UGA Cooperative Extension: Pruning Ornamental Plants in the Landscape

Pruning Fruit Trees

NC State Cooperative Extension: Training and Pruning Fruit Trees

Pruning Crape Myrtles

Clemson Univ. Cooperative Extension: Crape Myrtle Pruning

Note: Look for Cooperative Extension resources that are from your state or similar climate for the most accurate timing to prune.

Recommended additional reading: The Pruner’s Bible by Steve Bradley