Garden Tip #52

Winter is a good time to prune because the branch structure of trees and shrubs is clearly visible. Winter is certainly not the only time for pruning, but the list of competing garden chores is typically shorter in winter. Here are a few websites to check out before pulling out the pruning saw:

Washington State University, Mt. Vernon – a primer on pruning fruit trees
http://www.homeorchardsociety.org/growfruit/trees/how-to-prune-fruit-trees/ – five principles for pruning fruit trees
Plant Amnesty on pruning hybrid tea roses
Plant Amnesty on general pruning
Pacific Northwest chapter, International Society of Arboriculture – why and how to hire an arborist
Virginia Cooperative Extension – basic pruning shrub guide with illustrations.

Garden Tip #78

By Thanksgiving most leaves have fallen off deciduous trees. Some people feel a strong desire or obligation to prune when they see these naked trees. If you’re one of these people remember that most trees and shrubs don’t require regular pruning, other than to remove dead, dying or diseased branches. However, if some correction or thinning is necessary arm yourself with one of the excellent pruning books:

Cass Turnbull’s Guide to Pruning: What, When, Where & How to Prune for a More Beautiful Garden (Sasquatch, $17.95) – Turnbull demystifies pruning with humor and helpful diagrams.
The Pruning of Trees, Shrubs and Conifers by George Brown (Timber, $29.95) – This classic reference work has been revised and enlarged by Tony Kirkham to reflect recent advancements in pruning; it includes a plant by plant guide to special considerations.
An Illustrated Guide to Pruning by Edward Gilman (Delmar, $26.25) – A text book for professionals or serious gardeners, this book includes information on training young trees and has many illustrations.

Garden Tip #395

Wondering when is it necessary to clean or sterilize your pruning tools, and how to do it? Washington State University Extension horticulturist Linda Chalker-Scott offers excellent “how-to” advice. Make sure there is no excess dirt or debris on your pruners before you clean them. There are quite a few impractical or inadvisable methods (formalin? chlorine bleach? no!); her preference is to use ordinary household cleaners.

Another factsheet discusses when to sterilize your tools. Chalker-Scott says that first you must know which pathogen is causing the disease. Then,

“if it’s a virus or viroid, disinfect your tools.
if it’s a vascular fungus or bacteria, and/or forms oozing cankers, disinfect your tools. Avoid cutting active, oozing cankers; wait until they dry.
if you are pruning irreplaceable plants, disinfect your tools.
choose a disinfectant treatment that has been shown to be effective through published research; I would probably not use alcohol but one of the common household cleaners at full strength.”

Garden Tip #79

Use the right tool for the job. Bypass pruners (with blades arranged like scissors) make the cleanest cut. Anvil pruners may feel more powerful, but the blade tends to crush small branches, leaving a jagged wound more vulnerable to rot. But anvil pruners are essential if wrists are weak. If bypass pruners aren’t working it’s time to move up to a lopper or a pruning saw. For a concise discussion of all the various pruning tools go to: http://www.hort.purdue.edu/ext/pruningtools.html

Garden Tip #15

A common question gardeners have is when to prune. “When the shears are sharp!” is the often-heard answer. In reality there are a few timing guidelines that do matter.

First of all, certain trees are known to “bleed” when pruned while the sap is rising in late winter and early spring. Maples, dogwoods, birch, elm, walnut and honey locust are the most common.
Bleeding usually won’t hurt the tree, but the pruning cuts are slower to heal which may leave susceptible trees vulnerable to infection. These trees should be pruned right after leaves fall off in autumn.

Cherry trees are at risk from the destructive cherry bark tortrix. The tortrix is attracted to fresh pruning cuts, so cherry trees should not be pruned between May and August when the tortrix is active.

Spring flowering shrubs should be pruned immediately after flowering so that the new growth has time to form next year’s flower buds. Summer flowering shrubs may be pruned in winter because flowers are formed on this season’s growth.

Pruning resources online:

A guide to pruning trees and shrubs from University of Minnesota Extension
A Google search of “pruning” limited to .edu sites (Cooperative Extensions links)

Garden Tip #178

American Horticultural Society Pruning and Training. Christopher Brickell, editor. New York: DK publishing. 1996
This book gives detailed instructions on how and when to prune trees, shrubs, fruit trees, vines and roses. With good basic background information on general pruning techniques, pruning guesswork is eliminated. The book also explains how to do specialized methods of training like turning your hedge into a living sculpture.