Happy New Year: Time to Think About Pruning!

Introduction

Pruning is an often overlooked and/or wrongly-timed yard maintenance item. Basic, do-it-yourself tree and shrub pruning is generally uncomplicated but there are several things to consider if you are a beginner. This article will offer resources for DIY winter pruning, review best practices for the backyard tree keeper, discuss pruning times for some drought-tolerant cultivars that are staples of the Lethbridge urban forest, and suggest three local arborists/companies from personal recommendations.

Seek good information

If you have installed new plants in your yard, it is helpful to ensure that you retain the information about the cultivar for pruning. Many plants require little to no pruning, other than removal of dead or damaged limbs, but some flowering shrub varieties require extensive winter pruning to ensure blooms during the growing season. If you are unsure of your plants, take a season to observe and head to your local garden centre or seek out an arborist for information on the plant and how to manage it. For Alberta residents, it is important to know about Dutch Elm Disease and the provincial regulations governing pruning of Elm trees, which is banned from April 1 through September 30 every year. As far as learning about basic pruning techniques, there are endless instructions available from certified arborists online as well as short courses offered by garden centres and education institutions, like the University of Saskatchewan. Farmer’s Almanac has a comprehensive guide on how to prune safely and the government of Alberta also offers a basic overview.

Basic equipment

Quality hand pruners and loppers are likely all you require for winter pruning (consider garden snips/mini-shears for summer flower removal, fine pruning/shaping, and houseplant cleaning) as well as a sharpener and small wire brush to keep your tools working effectively.

Equipment should be clean and sharp; many horticulturalists recommend spraying cutting tools with bleach after cleaning/sharpening and between plants. Here is a quick video from Lee Valley describing easy cleaning and sharpening for pruners and loppers. Often local garden centres are well-versed in the tools that they carry and how to care for them and there is no shame in asking questions about maintenance and equipment care for longevity. Furthermore, if you are buying trees and shrubs, be sure to ask about pruning requirements of each variety and request a demonstration on proper pruning techniques if you have never done it before.

When to prune common Lethbridge trees and shrubs

Trees

With the exception of Elms, you may remove dead/damaged branches or suckers (basal shoots, root sprouts) from trees at any time during the year without cutting into the trunk or healthy wood. Most trees benefit from pruning (if required) in the winter or early spring before bud break. Here are some common trees & shrubs with hardy, drought-tolerant cultivars and when to prune them:

Alder, aspen, buckeye, cherry, chokecherry, cottonwood/poplar, crabapple, hackberry, honey locust, linden, oak: prune late fall to early spring before bud break

Birch, maple: prune after fully leafed out (usually after late July). These trees have heavy sap runs and pruning them in winter or early spring will result in significant “bleeding”.

Spruce, pine: Except for dead and damaged branches, conifers have different pruning requirements and techniques than deciduous trees. Most young conifers do not require pruning unless they have been grown for a particular shape and large, mature trees should have an assessment done by an arborist if you require branch removal or resizing. Generally, shaping and bottom bough removal of old growth should occur when dormant (winter) and new growth pruning should occur in the spring. Never remove the leader (primary, upward growing stem) of a spruce tree without understanding that you will be required to maintain the tree in a form not natural to its growth. 

Shrubs

It is important to understand the pruning requirements of flowering shrubs if you desire robust flowers and healthy plants in your yard. Ensure you know the variety of your new plants (particularly hydrangeas, roses, and climbing vines) so that you can prune without affecting flowers. Some common types of shrubs and their pruning seasons: 

Viburnum, boxwood, buffaloberry, cranberry, potentilla, serviceberry/saskatoon, spirea with pink/red summer flowers, sumac, chokecherry, elderberry, goji berry, sea buckthorn: prune after dormancy in late fall to early spring before bud break

Ashleaf Spirea, spirea with white spring flowers, lilac, caragana, aronia, forsythia, mockorange, nannyberry, Russian almond: prune after flowering in spring.

Birch: prune after fully leafed out (July).

Cotoneaster: prune late fall to early spring before bud break and also accepts regular pruning of new growth through the growing season to retain shape.

Dogwood: hard prune (removing large amounts) late fall to early spring but usually prune only after flowering in spring to retain shape.

Ninebark: prune late fall to early spring or during the season to retain shape.

Choosing an arborist

When it comes to reducing the size or removing large, mature trees, it is very important to the health and safety of your other plants, your home, and the people around your property to seek professional guidance. Homeowners are financially responsible for the upkeep of large canopy trees, the removal of dead or damaged limbs, and for any damage that those trees cause to surrounding property. It costs far less to maintain trees with professional services than it does to pay for damaged homes, cars, or even people. When seeking an arborist, ensure they are certified for the work they do and carry proper insurance. Consider asking your local garden centre or arborists (who may be too busy to take your job) for recommendations. In Lethbridge, I have personally worked with (or been recommended to): Rossco’s Tree Service, Southern Alberta High Angle, and Middel Tree Care (who cleaned up all eight of our neglected large trees after we purchased our home in Lethbridge).

Conclusion

A healthy canopy in your residential yard is crucial to enjoying the outdoors in the warmer months and supports biodiversity. Having many trees and shrubs on your property can also give you some increased outdoor time in the cooler months in the form of pruning work and dead branch removal. Good tools that are well-maintained as well as understanding of basic DIY pruning techniques for trees and shrubs in your yard are foundational to robust flowers and healthy plants.