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emerogork2

Perenials that are just too tall and leggy

emerogork
9 years ago

I am successful in cutting back my chrysanthemums not only to keep them short and bushy but I also root many of the cuttings to give away as plants. Now I want to know if there are any adverse consequences in cutting back other perennials.

I tried it once with Bee Balm but figure I did it too late and got very little bloom. It did, however, double in size as a bed of plants.

I just read that Cosmos will be shorter and less leggy if I cut them back. Will I get any good results if I trim back Sedum, 6' tall heliopsis, Asters, Marigold, and fall blooming Phlox?

I know that I have until August 1st to cut back mums but when might it be recommended that I cut back others? I am sure it has to be done before they set flowers but how soon?

Does anyone have success with any of these already?

Comments (8)

  • Campanula UK Z8
    9 years ago

    Known in the UK as the Chelsea Chop because it is done at the same time as the Chelsea Flower Show (end of May), it is a good way of increasing bushiness and aiding support for a range of late blooming perennials - most especially phlox, asters, heleniums. I have left it as late as the end of June but our short English summers are not conducive to later cutting.

  • greylady_gardener
    9 years ago

    it may depend on what zone you are in also.....but not totally sure on that. I stop pinching my mums by the end of June. I guess it could be later if your growing season is longer.
    I had one cosmo cut right back to a couple of inches tall a couple of months ago, courtesy of the ground hog, and it did come back nice and bushy....but no flowers as of yet. I haven't checked it in a few days so not sure how it is doing now. Had it only been clipped back a few inches, it may have done better.
    I regularly pinch back my sedums and stick the pieces in a bare spot....they grow roots and do just fine and the original plant branches and gets more stocky and bushy.

    I recently read that tall asters can be cut back around the outside and the shorter stems will get bushy and kind of prop up the inner taller stems. I can't see why heliopsis wouldn't be the same.

  • arbo_retum
    9 years ago

    Tracy di Sabato Aust's fantastic book, The Well Tended Perennial Garden, has charts of what and when for cutting back. As for me, I regularly whack back (that usually means by 2/3 or 1/2):
    monarda (w/ this, i whack to stagger bloom time in a large swath)
    rudbeckia herbstsonne
    heliopsis Lemon Queen
    asters
    sedums
    eupatorium chocolate
    artemesia
    verbascum
    malva

    -mindy

  • emerogork
    Original Author
    9 years ago

    Malva? I have a plant that I call Malva but have no idea if that is what it is. Here is a pic of it. Can you post a pic of your said "Malva"

    When I look up Malva, it looks like a short Hollyhock. (Different from the plant that I was calling Malva) What does it do if you cut it back?

  • emerogork
    Original Author
    9 years ago

    I never thought about just cutting back the outer sprouts around the base. I wonder if this can be done in tiers. I could have high, medium and low flowers....

    Does anyone have any pics of anything like this?

  • kirawilliams
    9 years ago

    I think the Hollyhock-like malva you were looking at may have been the sylvestris malva. Your picture could be the moschatta malva. (I think).

  • emerogork
    Original Author
    9 years ago

    " I think the Hollyhock-like malva you were looking at may have been the sylvestris malva. Your picture could be the moschatta malva. (I think)."

    You got that right,...
    Thanks.

  • green_go (Canada, Ontario, z 5a)
    9 years ago

    My sedums 'Frosty Morn' had been always leggy , floppy and ugly towards the middle of the summer. I was almost ready to get rid of it completely when I read an advice on gardenweb about cutting it back by 1/3 in June to make plants bushy, short and non-floppy. I tried it this year and I love the result. I will definitely try this trick next year with other sedums like Neon and Autumn Joy. Same with New England asters.
    Here are 3 of my sedums 'Frosty Morn' now - full, short and attractive
    {{gwi:270898}}

    This post was edited by green_go on Mon, Sep 15, 14 at 19:41

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