All posts by adele

About adele

Adele Medina O'Dowd is a principal of Pruning by Design, an ISA Certified Arborist, Tree Risk Assessment qualified, studied Integrated Pest Management practices and is a Landscape Designer ( She has been designing and working in gardens professionally since 2007. She received a certificate in landscape design in 2009 from George Washington University and a bachelor’s degree in fine arts in 1988 from Washington University in St. Louis.

pbd Pruning Guide : Selective Hand Pruning

Pbd : PRUNING PHILOSOPHY & STRATEGY | adele medina o’dowd | 2/3/2020

Would you like to prune shrubs and ornamental trees in your own garden? Perhaps you simply want to understand how pruning can improve the look and health of your garden even if you recruit others to prune for you. Either way, that’s wonderful! Clearly, knowing about some some basics and techniques will set you off on the right foot, but how do you begin? Well, take a deep breath and step back, then use this philosophy to help you wrap your mind around a strategy that can guide you. By definition, Selective Hand Pruning means that you proactively select which branches to prune and by doing so, you will strengthen your shrub’s natural architecture, resiliency and ability to photosynthesize.


1st step : Stand back at the curb, front door or the edge of your yard and take a careful overview of your entire front or back yard. Prioritize pruning plants in your yard based on time of year and what looks healthy and what does not.

2nd step : Consider what is a plant’s natural growth habit?  — is the natural shape or form of a plant ever square? 

3rd step : think about the job/role of the specific plant within the yard – what is its purpose? Screening, Flowers, Foundation, Seasonal Interest, Wildlife Habitat, Fragrance, Soil Retention, Shade, what?

UNDERSTAND that plants in the wild do not grow into rigid geometric shapes.  If you consider what the ideal, natural shape is for your plants and picture what that looks like in your mind, you will see softer forms. Even if you would like to have a hedge or shrubs with a more formal shape, plant shapes are organic. It is not healthy for shrubs to be sheared and foliage to be cut in the middle, disrupting its food supply and creating wounds that take extra resources to heal. With some confidence and practice, it is not so hard to make good pruning cuts quickly. You can do it! When you are done, the best results will be evident if the yard does not appear to be obviously “pruned”, but rather, when it just looks healthy, rejuvenated and better.

APPROACH pruning a shrub or tree with the idea of being selective. Before you start, determining what you are trying to achieve, with one plant and within a plant’s grouping. Where are you encouraging growth? Are you trying to reduce size? Do you want to re-balance the shape, encourage fruit and flowers, and foliage. Don’t rush it. It may take more than 1 season to get there. Plants are resilient so you might be able to prune them “hard” but don’t expect to prune them into a shape that they will retain forever — doing that will cause them to become unhealthy “empty shells”. Remember that plants have a life cycle in which they have youthful growth, reach their full potential and then eventually decline with age. Manage your own expectations while implementing your vision. Be selective, be patient and think about the future form and health of your plant.


Now is the moment to make your cut choices. Choose between any competing or crossing branches and retain the best leader of your plant needs a strong one. If there are too many, eliminate some branches that emanate from one location, keeping the best for the overall plant structure. Expect to prune branches at different levels and layers within the canopy. Retain internal and secondary branches. Careful not to injure foliage and bark unwittingly, causing undue stress and literally cutting off food production photosynthesis in leaves and nutrient flow in the vascular system.

  • Prune no more than ¼ to ⅓ — pruning too much at once can stress the plant
  • Careful not to injure Branch Collars
  • Start by pruning out any dead or weak wood (always)
  • Prune long and too heavy branches so they don’t break in winter and get leggy
  • Prune crossing and competing branches that are too close and parallel
  • Prune suckers and waterspouts when the plant is dormant
  • Next let light and air in — make “holes” in the canopy evenly over the entire plant so foliage blends but light and air can filter down into the interior
  • Stagger and vary the depth of your cuts inside the plant
  • Then begin shaping the whole thing based on your vision and knowledge of the plant’s natural form, move forward, stand back, blur your eyes, look at the plant or group, as a whole
  • Consider the interior branch architecture — what should that look like even if you don’t see it from the exterior? Are the scaffold branches strong? Are the smaller, lateral branches balanced all over and nicely spread?
  • Careful with hollies and other plants with branches that shoot from new cuts — “hide” cuts further inside foliage or low to the ground
  • Careful in Aug/Sept — let shrubs remain a bit rough at this typically stressful time of year to conserve energy and foliage
  • Remember that evergreens shed leaves 3 times/yr and sometimes it’s good just to shake or hand remove the brown leaves or needles that are hanging on without pruning branches at all


  • CLEAN TOOLS OFTEN. Use bleach wipes or dip tools between plants, beds or areas.
  • Careful NOT to spread disease!  Look for pest infestations and also good predators!
  • Contain pathogens by having a bag or blanket right next to you as you prune, throwing them inside to keep infected trimmings and infested foliage together and OFF the beds. (Friends don’t let friends use leaf blowers. You can spread box blight with them).


Unless you are already hooked on the zen of pruning, we understand that sometimes it can seem like an overwhelming job. But pruning with your friends makes it easy. You can relax and keep each other company. When you prune with friends and family, you can compare ideas for which cuts to make or not to make and ask for extra eyes to help you see the plant or the grouping from different views, especially at a distance. This is VERY helpful when you are standing inside a big boxwood, a densely planted azalea bed, or standing on a ladder looking up into the branches of your Japanese Maple or Flowering Cherry. Talk about it, as you work. Offer to help your neighbor and ask them to help you. Pruning is really fun with friends! Learn and gain confidence together. Enjoy yourselves and you’ll be done in no time.


One of the most beautiful explanations of an elegant natural system : Compartmentalization of Decay in Trees or CODIT

Developed and described by Alex L. Shiga Plant Pathologist, U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station, Durham, New Hampshire and Harold G. Marx Research Applications Staff Assistant, U.S. Department of Agriculture, Forest Service, Washington, DC

Watercolor illustrations by David M. Carroll, Warner, New Hampshire. READ the full text and VIEW the clear illustrations.

“The CODIT system is based on two major points. First, a tree is a highly compartmented plant. Second, after a tree is wounded, the resulting defects are compartmentalized”…

by Alex L. Shiga and Harold G. Marx

Yellowwood Lollipop=bad

Winter dormancy is a great time to prune ornamental and young trees to improve their architecture, structural integrity and form. This Yellowwood [ Cladrastis kentukea ] was in real need of correction after having been pruned badly last summer.

BEFORE : If you look at the “Before” images below, you can see that previously, it had been pruned so that virtually every branch was cut so that each was the same exact length, assuming a weird lollipop shape. This shape is very unnatural and unfortunate for ANY tree! It almost looks like a fan. We often see trees that have been pruned in this fashion when the owner really only wanted for the tree to be shortened or neatened a bit. Pruning trees into lollipops is a bad idea for the tree’s health because, in the same way that shearing a shrub creates a more dense exterior shell of foliage, lollipop trees suffer from poor architecture that blocks light from the interior of the tree. Branches become long and spindly and can break more easily, there is much less interior foliage for photosynthesis, and the tree becomes stressed. Plus, it’s silly looking and awkward. You don’t want your tree to look and feel like a cartoon.

AFTER : To correct this, Pruning by Design made staggered cuts at many different levels in the tree canopy being careful to create a balanced, soft form. You can see in the diagram of the cuts above, that it is very possible to allow more natural characteristic branching by pruning the tree correctly. Trees grow in this way for a reason, because it provides an evolutionary advantage. We keep and encourage a strong leader and main branches with shorter lateral branches inside. We cleaned up broken or weak branches, and shortened some of the overly long side branches that extended over the walk and into the neighbor’s doorway. By creating layers within the tree, the tree’s future health is improved by allowing light and air circulation in, important for preventing fungal growth and insect attacks. The Yellowwood’s structure is now much more graceful, too. Now it looks like a tree, not a lollipop.

Annika removing a “hanger” with clean cut that will heal better with CODIT “response growth”, preventing microorganisms to invade the old wound.

2020 Urban Tree of the Year : Celtis occidentalis

Info brought to you by Casey Trees
Celtis occidentalis or the common Hackberry
Celtis occidentalis or the common Hackberry CREDIT: Blog Post By Jona Elwell January 27, 2020 Casey Trees

…“The hackberry has for centuries lived a life of unassuming existence – a wonderful shade provider from the Elm family with its shares of upsides and downsides – that no doubt lives up to its oft-cited nickname: ‘the unknown tree.’ When given the opportunity of rich, moist, open soil it has the potential to reach nearly 100’ high and last for well over a century – but most often it’s considered a medium-sized tree found in parks and wetlands, parking lots and open yards”… READ MORE

PbD January Pruning & Garden Calendar

What’s on your garden calendar in January? Time to make your garden plans for spring and continue with dormant season pruning while plants and trees will be less stressed. It’s also a great time to call in expert arborists to assess trees and shrubs, too.

The PbD team works on dormant trees and shrubs and Adele is an ISA certified Arborist. In winter months, we are better able to view the architecture and branch attachments to maintain the strongest and work to eliminate the weaker ones, so the tree or shrub can have a healthy balance. We are always careful not to damage branch collars when we prune. And of course, right now we can look for previous insect damage and get rid of the dead wood! Timing and precision are important. Here’s a short list of January pruning items in the Mid-Atlantic region:

SHADE TREES : oak, hickory, beech, black gum, poplar, sycamore, ginkgo

“BLEEDER TREES” : birch, dogwood, elm, maple, & styrax

TREE PRUNING CALENDAR from North Carolina Cooperative Extension Office / NC A&T University

WONDERFUL SHRUB CALENDAR from Virginia Tech Extension Office

Even in January, be on the lookout for Fall Cankerworm.

What the heck is IPM? Key Concepts behind Integrated Pest Management

Besides being wonderful, IPM–Integrated Pest Management–is a sustainable, environmental approach to managing insect pests and pathogens in our gardens and other urban and suburban landscapes. The acronym need not be mysterious or intimidating, on the contrary, IPM will become your “Go To” once you get to know it!

Friends of Foes? Psocids, also known as bark lice, hanging out on a Cherry Tree. Psocids are fungivores, not damaging to the tree. (photo : adele medina o’dowd)

IPM Control Tactics start to finish…

Monitor Key Pests and Key Plants : Learn what to look for in your own garden and decide which areas, plants and trees are most important to you. (If, for example, Azaleas and Rhododendrons are important to you, get help from the UMD extension office website to learn about common pest and pathogens.) Get assistance in diagnosing and strategizing, as needed. Pruning by Design can help you with this!

Cultural and Sanitation Practices : Add biodiversity and native plants to your yard, include disease resistant plants, maintain plant health, the right amount of mulch; reduce habitat and soil stressers. Make sure irrigation is not too much or too little. PbD can help you with this!

Mechanical and Physical Controls : PbD can help you with this! PRUNE! Prune out infestations and hand pick to remove problem insect pests, use high pressure water spray to blast them off. Prune to encourage airflow and remove disease vectors.

Biological Controls : Implement these after working with other good plant health care practices, encourage or establish predatory insects such as lacewings and lady beetles to pray on pests like aphids, attract and support birds in your own garden, add beneficial nematodes in your soil, strive for a natural balance of predator and pray insects in your yard so that pest outbreaks are less likely. PbD can help you with this!

Chemical Controls : Last Resort, use organic and inorganic pesticides only on a prescription basis, applied by professionals. There is real and present danger for pollinators and other beneficial insects, as well as humans, when they are used in our neighborhoods. Check out your pesticides with the OMRI, Organic Materials Review Institute. PbD does not use chemical controls.

Don’t use fertilizers. Nitrogen, common in nearly every fertilizer, can actually promote secondary pest outbreaks that are worse than the first infestation, sigh!