When is a Prune Not a Prune? When it's a Plum!
Q. Anittah in Rose Valley, PA emails us a timely question: "Okay, I get it: I'm not supposed to prune in the fall, not even to assuage anxieties about the uncertainties of our times, and not even if it's going to be a beautiful and sunny 70 degrees F. Fine! (Harrumph.)
"But what exactly does it mean to prune? If I snip a beautiful bloom from a mature rose bush to admire indoors in a vase, have I pruned it? If I lop a soggy flower off a chrysanthemum, did I just prune it? What about a dead bloom from a butterfly bush? Am I allowed to snip hanging chads from my droopy Montauk daisy, or is any cut going to stimulate growth and turn me into a plant murderer?
"In other words, at what point does a snip become a prune? Are some autumnal snips desirable and, dare I say it 'plum'; or are all snips made in the Fall prunes?"
A. Great question Anittah, and as a reward for asking it I will for once (and maybe just this once) reply with a direct answer: All cuts are NOT the same, and yes, some removals of plant parts are actually beneficial in the Fall
Let's start with your specific questions and then we'll double back to your beautiful late Fall sunny day.
"What exactly does it mean to prune?" Sometimes the simplest questions are the hardest to answer, so I turned to the official definitions online. 'Vocabulary dot com' says that "To prune means to clip, crop, and cut back. Pruning usually happens to overgrown trees and bushes but can also be helpful for wild eyebrows and guest lists that are too long."
Not sure that anyone has ever said "I'd love to come over, but I need to prune my eyebrows". However, the guest list mention reminds us that the word has meaning outside of horticulture. Although I would 'thin' a guest list (which is also a horticultural term) rather than attack it with sharp bladed instruments.
'Dictionary dot com' simplifies the definition with "removal of branches, twigs and roots" and notes that the origin of the word (used in Middle English dating back to the 14 and 15 hundreds) means (in Middle French) to cut back vines; which is derived from an older Latin word that means 'to propagate'.
Bingo! As I have been stressing for decades, pruning = stimulation of growth, or the propagation of a bigger plant, not a smaller one. 'Propagation', of course, also refers to obtaining the material necessary to attempt the growth of a duplicate plant, like new green shoots in the Spring.
But all the definitions I found specify or allude to large portions of a plant, not the specific parts you ask about, which is why I love this question, as almost all of your examples are not about pruning per se, but dead-heading, which does not involve travelling around the country in a vintage 23-window Volkswagen bus, but the removal of spent flowers.
Your exorcism of soggy chrysanthemum flowers, dead butterfly bush blooms, and hanging chads from drooping daisies are all examples of dead-heading and not pruning. But the devil is in the details, the dose makes the poison, and you can't judge a good comic book by its cover. If you simply remove the spent, droopy, and/or soggy flowers alone, it should not stimulate new growth, which as we always stress is very bad for plants when winter is round the bend. But if you get a little frisky and start cutting back the stem, new growth could occur, which would be bad.
That's why I deadhead by hand in the Fall. I pull on my favorite hand protection (tight-fitting baseball batting gloves) and pluck the dead or dying flowers off the plants. Same with my precious raspberries; when they're done for the season, I gently use gloved hands to work off all the dead areas at the tips of the canes that once were clusters of fabulous little fruits. Such deadheading is good for the plants; and in the case of raspberries, gets rid of some pretty spooky looking claw-like things.
Your rose question, however, is trickier. My roses often continue to bloom right through light frosts, and their flowers are the last viable plant parts to expire as winter weather approaches. Just this year, I was tempted to bring in a perfect pink long-stem rose that bloomed after Halloween but was afraid someone might see me and rat me out. And the rose was right up front in the garden, helping to achieve an impression of my talents that reality might otherwise suggest.
A nice compromise might be to cut the flower right below the rose hip, perhaps with an inch or two of stem left connected, and display it in a clear glass bowl with water and some marbles to help keep it upright. (A trick that I learned from Martha Stewart. Really!)
And finally, that tempting warm day in the Fall or Winter is the worst time to do any of this work. A little pruning at this time of year is fine if you wait until the middle of a week-long cold spell, when your plants will be sound asleep.