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Top Questions About Knockout Rose Bushes

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Questions About Knockout Rose Bushes

  • Answered by
    MichiganDot on
    April 28, 2018
    A.

    It would have to be a large container (with drainage holes) for a Knock-Out rose to grow and thrive. I'm thinking 24" across and 18" deep. If you live where winters are cold, protection of above ground roots from freeze and thaw cycles is vital. Use potting mix, not garden soil and a long-acting fertilizer. Another concern is being blown over in storms. Consider adding a brick or good-sized stone in the bottom of the container. A better choice for growing in pots is the landscape rose. These only get 2 ft high, bloom prolifically and are available in many colors. One brand is OSO Easy.

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  • Answered by
    roseman on
    May 3, 2018
    A.

    There are a few things you can do. However, you have to be careful with thick foliage on roses. The foliage can get so thick that proper air movement through the bushes is impeded. Then starts the problems with fungal diseases that can be very hard to gain control of until proper air movement is restored. You can try using a higher in nitrogen fertilizer but go slowly! Too much nitrogen and the foliage takes off and blooms go way down and sometimes go away. Giving your roses 1/3 cup Epsom Salts sprinkled around the base and watered in lightly can help. Also look at giving them some Kelp Meal and Alfalfa Meal. 1/2 to 1/3 cup around the base of the rosebushes, worked in lightly and watered in. I would not apply it all at once, wait a couple weeks between applications. You could do two of them at once but I would not do all three at once. For a good liquid rose fertilizer check out the Urban Farm Premium Rose Fertilizer.

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  • Answered by
    MichiganDot on
    May 4, 2018
    A.

    If you want an indoor rose, go with miniature roses. KnockOuts are difficult to grow in containers. This shrub will have roots that extend at least 3 feet wide. You describe a "window box" that is large. That sounds too small but maybe I lack imagination. Bringing it indoors removes the trigger of cold weather that induces dormancy. Dormancy is followed in spring by a warm up that brings new growth. Did you keep it watered? Even when dormant, plants need some moisture to keep the roots from drying out. If you see no growth, slide the plant out of the pot. If the roots are dried out, the plant is dead. Also, in general, don't fertilize until new growth has started.

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  • Answered by
    roseman on
    May 11, 2018
    A.

    This looks like pesticide burn from spraying roses foliage on cloudy days or late in the day. The product stays on the leaves in liquid form too long and burns the foliage. Usually a spray is mixed just a bit to heavy or above the on the label instructions and thus burns the foliage. It can also be caused by water from lawn sprinklers getting on the roses foliage during the hotter parts of the day and the water acting like a magnifying glass directing the suns rays onto the foliage, thus burning it. It does not look like insect damage.

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  • Answered by
    MichiganDot on
    May 10, 2018
    A.

    Knock Out roses are mildew and black spot resistant but they still get these problems. No one will tell you that overhead watering is a good idea but roses survive rain, right? If you must, only water in the morning so the sun will quickly dry the leaves.

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  • Answered by
    roseman on
    May 13, 2018
    A.

    A very good question and something everyone should consider when planting any type of rose. Knock Outs are shrub roses and do like their "elbow room" so to speak. Here is a link to an article I wrote on this subject: https://www.gardeningknowhow.com/ornamental/flowers/roses/spacing-roses.htm

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  • Answered by
    MichiganDot on
    May 14, 2018
    A.

    Knock out roses get to be 4 ft tall. Even in a large container, it will be prone to blowing over in a good thunderstorm. I don't think it will do well in winter unless you insulate the roots by placing bales of straw around the container then wrap the bales and plant with burlap. You'll need to gently water it in winter so the roots don't dry out. If you are looking for a minimal care rose for a container, why not go with a landscape rose. It won't need the large container that Knock-Outs do and can therefore be easily moved to a shed or garage in winter.

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