Spring is the best time for pruning many, but not all, shrubs.
Luis Sinco • Los Angeles Times,
It's prime time to prune
- Article by: Rhonda Hayes
- Special to the Star Tribune
- April 1, 2014 - 2:40 PM
No gardening chore causes more consternation than pruning shrubs.
Maybe it’s because, no matter how vehemently we deny it, we’re judged by the appearance of our front yards and those often-prominent foundation plants. No one wants to be that neighbor. (You know, the one who lets her shrubs get “out of hand.”)
Turns out there are more important reasons to prune your shrubs, especially the beautiful flowering varieties. Proper pruning, done at the right time of year, promotes healthy growth, improves the quality and quantity of flowers, while keeping things a manageable size.
Here’s a you-can-do-it primer on pruning.
When to prune
You’ll often hear pruning recommendations based on “old wood” and “new wood.” But that can get confusing. It’s easier to think about when flowering shrubs bloom, in spring or summer. That can determine when to prune.
Spring-flowering shrubs— like lilac, viburnum, chokeberry, weigela, mock orange and flowering cherry — should be pruned right after they flower because the buds for next year’s blooms will form on this summer’s growth.
Summer-flowering shrubs — such as smooth hydrangea, smokebush, snowberry, potentilla and Japanese spirea — should be pruned in late winter or early spring because those buds will form on new growth the same year.
Pruning at the wrong time typically won’t kill a plant, but you may sacrifice flowers for that season. That said, it’s not wise to prune in late summer, when shrubs are sprawling. Doing so stimulates a flush of new growth that won’t have time to harden off before cold weather comes.
Choose the right tools
Save those hedge shears for hedges. You’ll want a more precise cut. Hand-held pruners are great for pencil-size stems. Loppers can handle larger branches up to 1½ inch in diameter. Resort to a pruning saw only for bigger branches.
To protect your fingers, wear heavy gardening gloves. And while it may seem like overkill, glasses or safety goggles will keep errant branches from harming your eyes. Also, watch out for large branches as they fall. If branches are near power lines, it’s best to call in a pro.
It’s a good practice to disinfect your tools with rubbing alcohol or a diluted bleach solution between cuts to avoid spreading disease from plant to plant.
The kindest cut
Always cut on a slight angle close to the wood, but not so close that you cut into the main stem. An angled cut sheds water and quickly heals.
Prune ¼ inch above where there is a bud. Choose a bud facing to the outside of the plant to direct growth outward.
Look for the three D’s: dead, damaged or diseased branches.
Cut broken branches back to healthy wood. Take brittle dead branches back to the base. Look for crossing branches that can rub together, causing a wound, and remove these potential problems now. For older, overgrown shrubs that haven’t been pruned regularly, you may have to cut back crossed branches in stages over several seasons.
Thinning, the most common pruning technique, is often needed for shrubs that sucker from the base. (Suckers are those vigorous, often upright shoots.) Removing suckers is the best way to renew a shrub while maintaining its shape. Remove up to a third of the oldest stems, cutting them at the base. In addition to making the shrub look better, it will allow for better air circulation and stimulate new growth.
Shaping or heading back is more like a haircut and is best used on shrubs that have grown over walkways or obscured windows. Trim branches back to a larger branch or bud maintaining the natural shape of the shrub as you go. Taking a shrub back down to size not only looks tidier but also brings flowers back to eye (and nose) level for greater enjoyment.
Rejuvenation pruning is more drastic. It involves cutting back the entire plant to the first buds, anywhere from 4 to 10 inches from the ground. This type of pruning is best suited for summer-blooming Japanese spireas and smooth ‘Annabelle’ hydrangeas.
Alternatives to pruning
If you don’t want to spend time pruning, consider buying compact plants. Smaller yards — and busy gardeners — have led breeders to develop more compact versions of traditional shrubs, which maintain their shape and rarely need pruning. Check out Hummingbird clethra, Java Red weigela, Compactum dwarf cranberry, Little Princess spirea and Snow Day Surprise pearl bush, among other petite options.
Rhonda Hayes is a Minneapolis-based garden writer. She blogs at www.thegardenbuzz.com.
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