Change Bloom Time on Your Perennials

PenstemonPlant

Penstemon and Salvia

You can do that you know by cutting them back at the right times.

Each time you cut certain perennials back, it will take about 2-3 weeks for them to rebloom if you foliar feed to jump-start them. If you cut them back too early, you won’t see the benefit, but cut them back in July, the plants speed ahead to more bloom.

If you want plants to bloom in September for instance, cut them back late July. If they normally bloom in August, give them a good cut at the end of June. Foliar feed and it will be faster.

Shasta_In_Garden

Here’s a trick designers use.

Take a mature perennial and cut it back in stages. Leave the back of the plant to grow as nature intends, but take the front-half of the plant and cut it back to half its size in late May or early June. Cutting time depends upon how fast the plant grows and what time during the season a plant will bloom.

Above, the sage cut for rebloom, the gallery below when it was just cut. Click to see the penstemon and sage just cut. You can see how this method becomes easily a benefit to the garden. A few weeks later, the front portion will flower. No staking is required since the bulk of the plant has been cut back. They will not flop in the garden now as the growing front part will now support the back half.

The front of the plant that was cut will begin to bloom weeks later than the back half.  As the back half is finished, it can be deadheaded and hidden by the blooming front half.  The new bloom hides the back side’s detracting foliage from view. It doubles bloom time. See the gallery above as I cut both Salvia nemorosa and Penstemon digitalis ‘Husker’s Red’.

Pink-Monarda

Delay blooming of one plant if you find it clashing with neighbors. Staggering bloom times can prevent moving a plant to another location.

Some perennials have unattractive bare or brown stems with still blooming flowers on top.  Hide what you don’t want to see by this step-cutting method and spread out the bloom time for many more weeks.

I have used this technique on Echinacea, Monarda, Shasta Daisy, Veronica, Asters, Nepeta racemosa ‘Walker’s Low’, Hibiscus, and Campanula grandiflora among others. Try it.

Hibiscus

BellFlowerCampanula

More ideas in Spring for Summer gardening to follow.

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About Garden Walk Garden Talk

I love to photograph, paint, draw, design, garden, travel the world, and pass on a few tips and ideas that I learned through experience as a Master Gardener and architect. I am highly trained in my field and enjoy my work each and every day. I garden in Niagara Falls, NY in zone 6-B. Find me at: http://gardenwalkgardentalk.com
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23 Responses to Change Bloom Time on Your Perennials

  1. Great tips, thanks so much.

  2. Victor Ho says:

    Great! I never put that together. We’re making a perennial garden and will put this immediately to the test.

  3. This is great ‘rule of thumb’ stuff.
    In my past gardens, I’ve done alot of pruning of perennials based upon the ‘deadheading’ rule/trial and error method and always wanted this type of info.
    My old gardens did flourish, especially the roses…which are another subject altogether, I know.

  4. Will have to try this. It most likely won’t work on my hibiscus though because they bloom so late.

  5. Interesting information.

  6. alesiablogs says:

    I have that native area I just let be mostly, but do have to fine tune it here or there!! I will have some stuff blooming while you are here I think!!

  7. swo8 says:

    Thanks Donna. Great tips.
    Leslie

  8. Great advice. I do this with some of my plants. And I also have several plants that I deadhead throughout the growing season for continuous blooms. It will be nice to move into blooming season, won’t it?

  9. rose says:

    This is a great idea, Donna. I cut back most of my fall-blooming perennials, like asters, mums, and sedums, but I haven’t tried it with others. I especially like the idea of cutting back just the front half to stagger the blooms. Thanks, I’m going to try this!

  10. I use this method on my garden phlox so that it blooms in September when I return from Maine. It also makes it bushier which I like. I am not so organized with cutting anything else back!

  11. rogerbrook says:

    They call it the Chelsea chop here in England as Chelsea week seems to work for a lot of perennials.
    Not only does the technique often delay flowering it is used to make the plant more compact.
    I imagine there are such plants as agapanthus where the technique would be ill advised.

  12. Indie says:

    Love this tip! I’ve cut down plants to make them shorter and bushier, but I love how cutting half extends bloom time. I should try this, especially with some plants that seem to have such short bloom times.

  13. I’ve cut back my swamp sunflowers in July so they don’t get so tall and still have a bloom season in fall. I think this idea could work well for a garden walk when you want plants to be showy for this event.

  14. Kevin says:

    Really great tips. I like the “designer” tip — to cut back the plant in stages. It makes perfect sense!

  15. At your suggestion, I’ve tried that trick of cutting back in stages – it works great! And I never thought of cutting back Penstemon, I’ll have to try that this year. What about Ratibida or Joe Pye Weed – do you think cutting back would work with them?

  16. Annette says:

    I’ve tried it too with different perennials and it works great also for Penstemon.

  17. Karen says:

    How interesting, wish I had known that when we lived in New England.

  18. A.M.B. says:

    Wow! What wonderful tips (and fabulous pictures!).

  19. debsgarden says:

    Thanks for the tip. While I am familiar with cutting back, I had never heard of the step-cutting method. I will definitely try it. Thanks!

  20. Andrea says:

    Hi Donna, we also do that in the tropics especially for foliage plants. I always do that with Sanchezia speciosa and our Mussaenda. But of course the time differs because we only have 2 seasons, the dry and the wet.

  21. I’ve bookmarked this one, Donna. New to me, I’m going to try it this year. Thanks. P. x

  22. Kl says:

    This is such a great tip. Will definitely try it out. What sort of foliar feed do you give?

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