To Chop, Or Not To Chop

Late May and early June are the days to cut back your tall perennials in this part of the world. I’m talking about cutting back before flowering, not after. Which is to say, cutting back to achieve a more compact, bushier, and less floppy plant.

3 Cutting
This is me cutting back dead plants in early spring, so a bit off topic, but you get the idea. 

This is kind of an urgent issue for our garden because we grow so many tall plants and they tend to flop over. Flopping plants make me break out in a rash, as I am afflicted with plantacaderephobia – fear of flopping plants, from the Latin planta (plant) and cadere (falling).

Which leads to the question, what gets chopped? When it comes to certain plants, I feel insecure about chopping. I don’t like delaying the flowers (one result of cutting back), and what if they don’t flower at all?

As of now, here are some examples from my list of plants to chop in late spring. I’m curious if they are consistent with your own experience.

New England Aster
New England Aster

Asters. Pretty much all the Asters except for White Woodland Aster (Eurybia divaritica), which stays nice and short. In the Front Island Bed, I have a two-level approach with the New England Asters (Symphiotrichum novae-angliae). The ones in the center I leave alone, but the ones closer to the sides get cut back hard. Some people cut this plant back twice, but I don’t like the idea of delaying bloom for so long.

Yellow Coneflowers (Ratibida pinnata). These are a challenge with their tall, thin stems. For the first time, this year I cut them all back hard in late May. We’ll see how they respond.

Brown-Eyed Susans (Rudbeckia triloba). Responds well to cutting back hard in May or June. This spring I also cut back one of our two clumps of Golden Glow (R. laciniata). So far the downsized one hasn’t gotten over the shock.

2014-09-01 17.11.03 Brown Eyed susan, black eyed susan
Black and Brown-Eyed Susan in the Parkway Border. Keeps passing drivers awake.

Bluestem Goldenrod (Solidago caesia). Definitely a good candidate for cutting back, at least in my experience.

Anise Hyssop (Agastache foeniculum). Takes downsizing in stride. Otherwise becomes unwieldy and overgrown.

Tall Ironweed (Vernonia altissima). In my garden “Ironweed” is kind of a misnomer. Rubberweed might be more like it. Some of the stems have begun growing in a loose corkscrew shape. These I cut back and stake.

There are those who might point out that perhaps these plants are getting less sun than they need. Or they might mention that I should arrange the plants so that they hold each other up. My response to these people is this: mind your own business. Also: LA, LA, LA, I CAN’T HEAR YOU!

Cup Plant, Silphium perfoliatum
Cup Plant. Yeah, it’s tall. You got a problem with that?

While I think the light could be inadequate for a couple of these (the Ironweed, for instance) I think a bigger factor may be rich soil. These plants are mostly wildflowers and they are not acclimated to garden conditions. In rich soil, they become overgrown. These days I don’t fertilize them or even add organic amendments beyond the dormant plant matter generated within each bed.

As far as my “no chop” list, I refrain from cutting back Monardas, Joe Pye Weeds (Eutrochium), Milkweeds (Asclepias), Culver’s Root (Veronicastrum virginicum) and Cup Plant (Silphium perfoliatum).

What plants are on your chop/don’t chop lists? Have you ever cut something back only to regret it later?




64 Comments on “To Chop, Or Not To Chop”

  1. I don’t cut back any of the flowers. I don’t have your kind of phobia and think, some toppled over and bend blooms can look quite romantic. But I have to say: by no means do I grow as many tall flowers as you do, so this is easy for me to say.

  2. It is called The Chelsea Chop’ here, because it is best done at th same time as Chelsea Flower Show. I have never been brave enough or had enough forethought to try it. Plantacederephobia- lovely one, did you make it up?

  3. Ooooo, Jason’s feeling a bit belligerent (or is it defensive) today, lol. We all love your splendid gardens, dear! I chop my tall mums (Cambodian Queen and Sheffield Pink) twice, cuz if I don’t, those enthusiastic plants get 4′ tall and flop. And I root the cuttings so I can have more. Chopped half my fireworks goldenrod as an experiment this spring. Ever propagate your trimmings?

  4. I’ve never chopped back a plant. Don’t have any of the plants you listed. I do, however, have flopping irises, and I know just what you mean. Seeing them flop fills me with utter despair.

  5. Here (western Virginia) I chop aromatic & New England asters and garden phlox twice: Memorial Day and the 4th of July. The dates are just a mnemonic device; the cutback (about a third of the way) happens in the second half of May and the first half of July. The first chop is a real pain because there’s so much else to do then: planting and transplanting, deadheading early irises and peonies, edging, getting cool-season annual weeds before they go to seed…

    These plants are in full sun. They bloom later and more bushily due to the chop, but the real beneficiaries are the plants around them, which greatly benefit from the increased air circulation and light. Being forced to deal with them early on also gets me to reduce the clumps that have gotten too enthusiastic, and allows me to spot things like sprouting black walnuts early enough to remove them completely. The second chop is not usually as big a job; in early/severe drought summers, it may not happen at all.

    Haven’t cut back Joe Pyes before, but inspired by comments here, may experiment with a portion of them. A very rainy second half of May has pushed them to greater heights than they’ve ever reached at this date.

  6. I didn’t need to cut anything back this year due to an explosive rabbit invasion. I did cut back some monarda due to some scorched (?) leaves, which I have never seen before. The extreme weather swings that seem to be the new normal make each year an adventure, to say the least.

  7. I don’t think I have ever chopped back a flowering plant on purpose, although I have noticed the difference when doing it accidentally. I have a copy of The Well-Tended Perennial Garden, but it just seems like so much (additional) work when there are more pressing needs (like weeding).

  8. Here is the comment I left for Jason on FB: Jason, I have been cutting back the Culver’s roots, Joe Pye, and monardas for a number of years. This year, I didn’t get as many plants cut back as early as usual, and some I have skipped, because I was sick, and I still don’t have all of my energy back. It does definitely delay bloom time. The one Culver’s root I didn’t get cut back this year now has blooms. I am curious to see when the others bloom this season. (I also cut back the ones you listed.)

  9. I usually cut back my asters and my achillea, but this year their growth has been so stunted by the dry and hot spring that it hardly seemed worth it… I will probably regret it but they do both have supports anyway! By the way, is that phobia real? Or are you pulling our legs?!

  10. Hello Jason and this is a timely post !
    Yes .. as a matter of fact I am hoping to get some of that accomplished tomorrow .. chopping and supporting (strange combination when you type it ? LOL)
    Chopping .. tall sedums, asters, some Joe Pye depending on position next to other plants ..
    I did do one of my veronicastrum last year , just to see what would happen .. never again !
    I trim up so blousy larger plants like goatsbeard and astilbe chinensis, they get a little too .. bold with their neighbors ? haha .. I go by instinct or previous experience .. mistakes have been made .. but you always keep learning as a gardener .. if you think you know it all ? that is the first indication that you DON’T ! haha
    Great post & pictures 🙂

  11. I cut back floppy agapanthus flowers… ours multiply every year anyway, but the year we didn’t cut the flowers … the seeds blew everywhere & we ended up with far too many agapanthus…( they are aptly named the bully boys of the garden here in Australia)

  12. Here in NC, I always cut back the asters pretty early — in mid-late may. I have some native October-blooming swamp sunflowers that can grow to 15 feet or more (and then in a hard autumn rain, flop over in dramatic fashion), and two years ago I experimented by cutting them back to various heights. Last year I cut them way back to just 18 inches or so in July, and they “only” got to 6 or so feet by October, which was a good height. Last spring I cut back the spirea aggressively, and it developed spikes of tall branches which have now flopped over. I’m going to cut it back, even if it inhibits more blooming this summer.

  13. Speaking of plants without enough sun it seems my entire garden is that way. I have a little more sun since losing a big tree in the back garden but it hasn’t helped much. I cut back asters and Sedums. Anything that brushes me when I walk by gets a good clipping too. Naughty plants.

  14. The Chelsea Crop, as we Brits call it, (because it is done at the end of May which is when the Chelsea Flower Show happens) isn’t really necessary here. Most plants don’t grow so tall because they are growing in tougher conditions with in my garden a very free draining soil. This year I might regret not cutting back the Sedums as they have already grown very tall due to the rainfall we’ve had this year.

  15. Hello Jason, in the UK people sometimes do what’s called a “Chelsea Chop”, which is where perennials are cut back by a third of half so that they flower more (but later). It’s called the “Chelsea Chop” because the pruning is done in late May, around the time of the Chelsea Flower Show. Personally, I don’t bother because I’m usually running around trying to get other jobs done that this kind of work is a luxury!

  16. I HATE to prune rhododendrons! I know how long it took for them to develop the bits of stem that I cut off. The problem is that some varieties get so tangled and sloppy after years of neglect. Even the tall ones that grow as trees need to be tucked back so that they do not fall over. HOWEVER, I find that most plants in the landscape do not get pruned enough, and it makes me so angry that big box stores sell deciduous fruit trees without any explanation that they need annual winter pruning. Fruit trees and roses are the worst for getting overgrown, and once overgrown, they are so susceptible to insects and disease.

  17. Lacking a garden, I don’t have any chop/don’t chop decisions to make, except when it comes to my cacti and dwarf schefflera. They certainly profit from an annual cutting back; my biggest problem is making myself either give away or throw away all those extra Opuntia pads.

    But I do see the effects of trimming everywhere, compliments of land managers, state and county mowers, refuge decision-makers, and so on. I’m often surprised by the resilience of the natives. Primroses, wine cups, clematis (of various sorts), goldenrod, and milkweed may come back shorter, but they do come back, and relatively quickly. Last week, our esplanades were mowed within an inch of their life. Today, they’re already covered by Mimosa strigillosa, Oenothera speciosa, and even some rain lilies, which apparently think a half-inch of rain is quite enough to get with the program.

  18. I’ve never cut anything back for the fear of not getting flowers – my Joe Pye Weed, though, could do with being a bit shorter as it does tend to flop into the path. I see you don’t cut yours back – do you think it will still flower if I do?

  19. So far I’ve cut back Kalimeris integrifolia, Heliopsis, Henry Eilers Rudbekia, Aster Lady In Black, a variegated Goldenrod and Persicaria polymorpha. Last year I cut some Phlox back but did not like the smaller flowers.

  20. I loved this post. I’ve found the same thing, that the natives I planted get way too tall from the rich soil and perhaps a little too little light. Hey. the squirrels hadn’t planted the oaks yet, what can I say? I’ve cut back daisy fleabane with good results, as well as the asters you mentioned. My liatris gets too tall and floppy but I’d be afraid to cut it.

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