So You Want to Change Bloom Time on Your Perennials?


Penstemon and Salvia

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

Each time you cut them back, it takes about 2-3 weeks for them to rebloom if you foliar feed. When you cut them back early, it has a minimal effect, but cut them back in July you will see a speedier change in growth.

If you want plants to bloom in September for instance, cut them back late July. If they normally bloom in August, bump that up to a hard shearing at the end of June.


Here’s a trick designers use. Take a mature perennial and cut it back in stages. Leave the back of the plant to grow normally, 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 after it was cut a week ago, 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 2-3 weeks later than the back half.  As the back half is finished, it can be deadheaded and be hidden by the blooming front half.  The new bloom hides the back side’s declining foliage from view. It doubles bloom time and also reduces the number of plants you might add to cover spent foliage. See the gallery above as I cut both Salvia nemorosa and Penstemon digitalis ‘Husker’s Red’.


If you have a clashing color combination, this technique can be used to delay blooming of one or the other. It might resolve moving one of the plants.

Some perennials will have unattractive bare stems. When they lose the lower, yellow leaves, the flowers may be beautiful but the foliage detracts.  By step cutting the front of a plant as mentioned above, you can create a layered effect to the plant, hiding what you would rather not see. This technique works especially good on one particular perennial or large drifts. Cut at intervals to spread out the bloom time for many more weeks.

I have used this technique on Monarda, Shasta Daisy, Veronica, Asters, Nepeta racemosa ‘Walker’s Low’, Hibiscus, Campanula grandiflora and Echinacea, among others. Try it. Nothing to lose and you might end up doing what the pros do to keep those gardens in continued bloom.


I hope you are enjoying some of the tricks of the trade. Coming up… Potting Up the Pretty Perennials.



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:
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14 Responses to So You Want to Change Bloom Time on Your Perennials?

  1. Oh, I haven’t been around for some time and I sure missed these blossoming pages!!!!
    Happy new week, my dear Donna! 🙂

  2. I never knew that! What a great trick!

  3. Indie says:

    Very interesting! I’ve pinched things like Joe-pye, but I’ve never thought to cut Hibiscus or Penstemon or some of the others. Great article!

  4. Alisha says:

    very informative and interesting article…thanks for sharing Donna..

  5. Sheila Daniel says:

    Great tip. Thanks for your continual help in makeing me a better gardner. I don’t often comment, but do often read.

  6. This can come in very handy. I also like, that with some perennials, hardy Geraniums for instance, you can let them bloom at the normal time, cut them back quite hard immediately after flowering and you will often be rewarded with a second flush.

  7. alesiablogs says:

    I love the second to last photo! I hope your trip is going well.

  8. johnvic8 says:

    this is great post. I have cut things back in the past with good results but it was haphazard, not based on the information you have included. Thanks.

  9. Great tip. I cut back all my garden phlox in the third week of July to make it bushier. I also cut back sedum autumn joy to keep it from flopping when it blooms. I will have to try some of the other plants you mentioned. That’s some hibiscus.

  10. Andrea says:

    Sometimes i do that too Donna, but our climate is different, so i cut back all of them at the start of the rainy season. In a few weeks they are like new. This is good for Hibiscus, Sanchezia speciosa. By the way that white hibiscus is so floriferous, and very beautiful.

  11. A.M.B. says:

    Wow, I had no idea you could stagger bloom time like this! It’s fascinating. I’m just building my garden now, so I’m not quite ready to do this, but I know I’ll refer to this post again in the future.

  12. Great post. I never thought of cutting back just the front part of the plant, but that makes perfect sense. I’ve cut back my Ratibida pinnata just last week and I’m thinking of cutting back the Veronicastrum because the foliage is yucky. i always cut back asters and tall goldenrods.

  13. That opening shot featured here is just incredible! How DO you do it? Don’t know which impresses me most …your photography skills or your gardening skills?!? Always a joy to see your posts.

  14. Donna this was fabulous…who knew about cutting the plant in stages…so much food for thought now!

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