Autumn inspires a rash of whackadoodle…

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Fall brings on the urge to clean up, but reconsider!

I was reporting for jury duty, feeling anonymous in a pool of fellow citizens, when the court officer asked me how far back she could prune her landscape roses this fall. I sighed, and as everyone craned their necks to see whom she had addressed, I told her as much as she likes…but not now. Maybe in March.

The calls about pruning start every autumn with the first breath of cold air. I should probably make a recording to save my own hot air, as I feel compelled to explain at length the many reasons that you should not prune in fall.

Autumn pruning can have several negative consequences. Done too early in fall, fluctuating temperatures and rain may induce the pruned plant to initiate a flush of growth. This tender new foliage will be singed badly by the first cold snap, so you wasted the plant’s energy stored for next spring’s flush.The cut stems will not heal through the winter, leaving the plant open to dessication, or even infestations of pest or disease. It will be spring before new growth can initiate healing and regrowth.

Photosynthates are stored in many parts of the plant including the stems and evergreen leaves.

A more obscure reason makes a strong physiological case. Through photosynthesis, woody plants accumulate carbohydrates that are stored in roots, but also in stems and even the leaves of evergreen plants. These starch reserves can not only play a role in winter survival, but also are mobilized and translocated as spring approaches to initiate and contribute to the new season’s growth. Fall pruning would undo much of the wonderful work your shrubs did all summer to build a better plant next year.

Many birds rely on dried fruit for winter food.

Other reasons to put off pruning are the benefits to wildlife. Not only might the plants have dried fruit that feed birds but they also harbor dormant insects that overwinter under leaves, in bud scales and even inside the stems. Many overwintering insectivorous birds have learned how to seek out these hidden sources of protein. Reducing the overall bulk of the plant is actually a reduction in cover as well. A dense evergreen shrub might be a cozy place out of the wind until a pruning made it less so.

Pruning is best done just as winter ends. The exception is spring flowering shrubs. Early pruning will nip off the flower buds that were set last summer. They should be pruned as soon as they have finished the bloom display.

Take note that winter’s end does not necessarily correspond with the calendar. Spring comes early some years and others years late. I look for clues in the landscape that spring is nigh. In this region, those signs may be the first rosy hues found in red maples while most trees are still decidedly gray and dormant, or the first daffodil buds pushing from the earth. Some years it it begins as early as February, though usually it is March.

Dense shrubbery provides shelter and harbors “dormant” insects that can be gleaned by birds.

Are there times to do pruning earlier in winter? If I had a lot of trees to do, say in an orchard, or a large landscape with overgrown shrubs requiring many hours of meticulous judgement, sure, I’d get an early start. Do I whack on a few plants for cut greenery for the holiday season? Like crazy I do! Tired of that overgrown shrub scratching your car door? Show it who’s boss.

Those are the exceptions, and though it seems there are always reasons to ignore best practices, for the most part don’t prune in fall (or early winter) and I saved my most heartfelt reason for last. It’s ugly. Why would anyone want to look at a shorn plant all winter? Those stems might be those that play gracefully in the winter wind, or serve as perch for a brilliant cardinal. The bleached flowers may still have lovely structure, gossamer reminders of summer glory, poised to be etched by frost or light snow.

Bare stems and frosted flowers have their own pale grace.

So, those pruners. Until 2019, put them down and back away.

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Carol Reese

Carol Reese is an Extension Horticulture Specialist housed at the University of Tennessee’s West Tennessee AgResearch and Education Center in Jackson. She is a nationally-known speaker, blending equal parts gardening knowledge, natural lore, and quirky humor.

Carol is the gardening and nature columnist for several newspapers, as well as a contributor to several gardening magazines. She was the Q&A columnist for Horticulture Magazine for several years.

Her B.S. and M.S. in Horticulture are from Mississippi State University, and she could also add her Ph.D. if she “had ever written that damn dissertation!” While there, she taught classes in Plant Materials, and co-taught Landscape Design for non-LA majors alongside a “real” landscape architect.

She attributes her love of horticulture to being raised on a farm by generations of plant nuts, including a grandfather who dynamited his garden spot each spring to “break up his hard pan”. Carol’s very personal appreciation of natural lore is at least partially a result of her near daily rambles through the wild areas near her home with her motley collection of mutts, also known as the strong-willed breed of “Amalgamations.”

 

10 COMMENTS

  1. Good post. I’m leaving the cone flowers, grasses, etc. up for the winter. No big rush to cut back anything.

  2. Last year I didn’t get around to pruning my lavender, and it was a joy all winter long, to walk past it and crush a dried flower head and get that burst of summer aromas. Plus, it was beautiful with a little snow on it. Yeah, I had to prune them this spring, and it probably wasn’t best for the plants to let them go over winter, but I enjoyed them all the same. I did prune/harvest the the flower stalks this summer when they bloomed.

  3. Love the title and the content! I cut down the herbaceous peonies, but leave up the Echinacea. Do people still cut down the ornamental grasses though? If so, what a shame! I love looking at the snow on the Miscanthus – and I have seen birds feeding on the seeds. I am considering pruning the Acer griseum once all the leaves are gone, but the pruners keep getting stilled since I am not sure how to prune it without encouraging it to spread even wider. Pruning like Horticulture is both art and science! Happy Fall all!

    • Because of the frost crystal show the grasses give I too leave them until just days before new growth starts. Missed it one year and all the ornamental grasses looked like Bart Simpson.

  4. A very good post. Heck, even our local nursery , which specializes in loads of native plant purchases and sales, destroyed large beds of blooming giant and state fair zinnias a few weeks ago, just as the numerous butterflies and bees were gathering nectar to fatten for the winter. All gone. (My own zinnias and tithonia are producing loads of blooms right now and I still have monarchs and numerous other species here in Maryland today). Here is what the nursery SHOULD HAVE LEFT STANDING, But didn’t: https://photos.app.goo.gl/TM3FqejbX6RAU2D46

  5. All the right reasons to wait on pruning in one concise essay. I’m sharing this on my FB garden page (Columbus Garden Coach). Thank you!

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