Cropping, trimming, snipping, nipping Do’s and Don’t’s for pruning shrubs in late winter

Welcome to February and March, the months when even the hardiest of gardeners may be tempted to stay indoors and avoid the wet, chilly Pacific Northwest weather. But before you grab your gardening gloves and pruning shears, let’s go over some dos and don’ts to keep in mind as late winter tries to move into spring.

If you don’t know how to prune, take time to learn how to do it correctly. Always use freshly sharpened bypass pruners. Learn the difference between heading and thinning cuts—the results of each technique are radically different.

Heading back is a method used to lower the height of various types of bushes by cutting each branch back to a bigger branch or bud. It creates bushy, dense new growth.

Thinning is the most popular and effective method for rejuvenating a shrub. It keeps the plant’s shape intact and is especially useful for shrubs that sprout from the base. To do this, use loppers or a pruning saw to cut interior branches back to the bottom of the plant or the point where they originate. It’s a good idea to disinfect the pruner between cuts with alcohol spray or a disinfectant surface wipe.

My favorite reference book is Cass Turnbull’s Guide to Pruning . There are some great videos out there, too. Our website has a terrific collection of reliable, research-based gardening information; check out cowlitzcomg.com/workshopsvideos.

Pruning may be necessary for many deciduous shrubs that lose leaves and go dormant in the winter. Go out and look at your bushes. Not all shrubs need to be pruned, but you should remove dead, diseased, and crossing branches and any suckers you see coming up from the roots (yank those out—don’t prune suckers). Are the shrubs overgrown and trying to take over your planting bed? Is the shape not to your liking? Are the inside branches bare of leaves? It might be time to consider some judicious pruning. Pruning a flowering shrub will also encourage more flowers to bloom.

What NOT to prune now: springflowering bushes, such as lilacs, forsythia, azalea, daphne, rhododendron, wisteria, snowball and lacecap hydrangeas, and many others. They should be pruned immediately after they have finished blooming—no later than June because they will form next year’s flower buds this summer. If you prune any of these right now, you won’t have any flowers this year!

However, now is a good time to prune shrubs that flower in the summer, such as panicle hydrangea (the ones with cone-shaped flower heads), spirea, camellia, abelia, California lilac, Russian sage, and others. They form flowers on the new wood that grows this spring, so prune them while they are dormant— before the leaf buds open. My panicle hydrangea grew into a monster last year. I plan to prune it down to about 6 inches this year, then give it some rose fertilizer to support new growth. This is called rejuvenation pruning, which can be stressful for the plant. The best and healthiest way

Story by Alice Slusher

to rejuvenate an overgrown or twiggy shrub is to prune it back by one-third for three consecutive years.

Don’t hesitate to begin trimming your plants. Acquire the necessary knowledge through resources such as books, videos, or websites and videos offered by universities like WSU and OSU. After gaining some understanding, grab your pruners and get started. Remember that pruning is not an exact science; it is an ongoing process of experimentation—and that’s what gardening is all about! •••

Programs & Events

OSU Extension Columbia County 503-397-3462

Online Workshops: Registration is required. extension.oregonstate.edu/county/columbia/ events

Feb. 18 OSU Small Farms Conference, Corvallis

Feb. 18 9am-noon Annual Grafting Workshop

Feb. 18 1-3pm Learn how to Prune Fruit Tress & Grapes, and to Set Mole Traps

Feb. 21 (6:30–8pm) Chat with Chip online interactive Q&A program with Chip Bubl.

WSU Extension Cowlitz County

360-577-3014

304 Cowlitz Way, Kelso, Wash.

For connection info or registration for in-person classes: cowlitzcomg.com/public-events)

Online Workshops. Tues., noon:

Feb. 14 Seed Starting at Home

Feb. 21 Grape Care and Pruning

Feb. 28 Rose Care in the Spring

Mar. 7 Growing Strawberries

In-person

Feb. 18 (10-11:30am) Seed Starting Class

Feb. 25 (10am–noon) Grape Care and Pruning

Mar. 4 (10am–noon) Raising Mason Bees

Mar. 11 (10am–noon) Willow Propagation