Knockout Roses Not Blooming

In CategoryKnockout Roses
knockout rose hedge

Knockout Rose Hedge

Knockout Roses are considered extremely easy to grow but like any plant in the garden their needs must be met. If your roses are not blooming or have decreased flowering there are a few simple ways to have them back in full color.  The most common reason for reduced flowering is lack of nutrients, especially with plants 3 years and older growing in poor soils.  The quick remedy for this is to fertilize the plants.  Start with a slow release rose fertilizer applied in mid-spring followed by a liquid feeding in mid-summer and again in late summer.    

The second most common reason that can cause Kncokout Roses not to bloom is plant size.  If the plants have been left to grow without any pruning  they will spend most of their energy on maintaining their size at the expense of flowering.  Knockouts do not need to be pruned as often as other roses but if you want to maximize their flowering potential it is best to prune the plants in late fall or very early spring.  Pruning will not only increase blooming but will help maintain the plants appearance and health.  

 The third tip for getting more blooms out of your Knockouts is to deadhead faded flowers – occasionally.  I know that all the marketing hype around the Knockouts claims that the flowers are “self-cleaning” and do not require deadheading.  It is true the flower petals will fall off all by themselves, but removing faded flowers is not the only reason for deadheading.  By pruning off the rose hips left behind after flowering you are removing the “seed pod”. Once the seed pod or hip is removed the plant can, and will, divert it’s energy from seed production to flower production.  You don’t need to run out with a pair of pruners every time a rose bloom fades but you will get better flowering if you deadhead 2 – 3 times per year.   

Knockout Roses are easy and will grow with basically no effort from the gardener, but why in the world would anyone choose to ignore such wonderful plants.   Give your plants the attention I described above and you will once again be rewarded with beautiful roses.  




6 Responses to “Knockout Roses Not Blooming”

  1. Carol Washington Says:

    Thank you for that tidbit of information. I really did not know how to care for these roses

  2. Patricia Says:

    Thanks! this is just the information I need.

  3. Carol Mahala Says:

    Thank you for this good information. My daughter
    has insisted that because they said “self-cleaning”, she didn’t have to do anything to them. She is a new gardener. I explained that it only made sense to prune and deadhead, but she refuses to understand or listen to Mother!

    I’ll copy this and send it to her. Thanks again.

  4. Constance Says:

    All of this is so true, I have one double red knockout by my garage door that I have never pruned in 4 years and it is well over 5 feet tall (that’s taller than me). It’s tall and thick and does continue to produce a full load throughout the year (yes including winter) but I have another that I pruned down to about 18″ and before summer was here it was back to half the size (3 feet) and others that I find that will do better if I deadhead every now and then. I believe this is due to placement and the amount of sun they receive. I found that even though they’ll grow if there is too much soil over the top of the plant, you will get plenty of green but no flowers at all. The good news is that once you push back some of the soil the blooms take off. I just love the knockout, you give it what it needs and it will always give you more than you bargained for. I just love them!

  5. Tra Says:

    Yes I do think you need to prune back the plants. This will not only help in producing flowers but will also promote fuller bushes and stronger canes.

  6. Tra Says:


    Knockout Roses are hardy in all areas of the US so you will not have to replant.

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