Home Improvement Expert Danny Lipford

How to Control Black Spot Fungus Disease on Roses

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Black spots and yellow leaves on rose bush

The signs of black spot fungus on roses are hard to miss.

Black spot (blackspot) is one of the most common diseases of rose bushes; and, if left unchecked, it can cause quite a bit of damage to your rose garden. Caused by the fungus Diplocarpon rosae, black spot begins just as its name suggests, with black spots showing up on the surface of the leaves.

As the spots grow larger, they become ringed with yellow, eventually causing the whole leaf to turn yellow and fall off. The stems may also have black or purplish spots. If not treated, black spot will leave your rose garden not only naked, but significantly weakened and unprepared for the next winter.

Like most fungal diseases, black spot thrives in wet, humid weather, usually when temperatures are in the mid-70s F. The spots produce spores which spread to other leaves and plants. The spores can survive the winter in fallen leaves and infected canes.

Rose leaves with yellowing and black spots

Leaves on roses with black spot eventually turn yellow and fall off.

While black spot may seem relentless in your rose garden, it’s actually fairly easy to manage with the right treatment and prevention strategies. Here’s how to control black spot in your garden.

How to Treat Black Spot

If you’ve noticed telltale black spots on your roses, you should:

Remove Infection

Prune away the infected leaves and infected stems. Also, rake up all the fallen leaves under the plant. Throw the infected debris away, rather than putting it on your compost pile.

Spray Roses

Spraying rose bush with neem oil

Neem oil fungicide for black spot.

Once the infected leaves and stems have been removed, treat your rose with a fungicide. Spray the entire plant, making sure to get the tops and bottoms of the leaves as well as the stems. You can use a chemical fungicide or any number of organic options such as:

  • Copper
  • Lime Sulfur
  • Neem Oil
  • Potassium or Ammonium Bicarbonate
  • Sulfur

How to Prevent Black Spot

With the right gardening habits in place, you can keep black spot at bay on your roses by:

  • Water in the Morning: This allows the moisture to evaporate from the leaves.
  • Avoid Watering Foliage: Especially if the weather is warm and humid, avoid getting the foliage wet when watering.
  • Choose Resistant Roses: Some varieties of rose are resistant to black spot.
  • Allow Air Circulation: Choose a planting site with plenty of air circulation, and be sure to space your roses 3-4 feet apart. Prune dense bushes to let air circulate between the branches.
  • Dead rose leaves on ground under bush

    Discard fallen leaves under rose bushes.

  • Choose Sunny Location: Roses prefer full sun anyway, and choosing a sunny location for your rose garden will help burn off moisture.
  • Keep Garden Clean: Regularly rake and clean up around your roses, and throw away any fallen leaves. This is especially important in fall and winter, to remove spores that might be awaiting the spring warm-up to become active. After the cold-weather cleanup, apply fresh mulch to keep any remaining spores away from your roses.
  • Stay Alert: Inspect your roses regularly, and immediately remove and throw away any spotted leaves, both on the plant and on the ground. If the problem isn’t severe, this may be all the treatment you need.
  • Preventative Treatment: If black spot is a perennial problem in your yard, begin a preventative treatment with an organic, nontoxic, fungicidal spray (such as those on the list above), right before your roses sprout in spring. Continue treatment every couple of weeks to keep the fungus under control.

Further Information



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5 Comments on “How to Control Black Spot Fungus Disease on Roses”

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  1. Karen Carr Says:
    December 7th, 2012 at 1:54 pm

    Love your show! Would you please advise on how to get rid of the pesky Japanese Beetle. I’d like my “rose restaurant” to be closed to them in 2013. Thank you.

  2. madlyn Fairbanks Says:
    April 1st, 2014 at 12:19 pm

    I am new at planting anything i have some minature roses and i noticed the speckled leaves on the bushes ,i have been picking the infected leaves off the plant not knowing that i was doing the right thing alas i did not dispose of the infected leaves i just dropped them on the ground thanks to this article i know now what to do thank you so very much.

  3. Debbie Morris Says:
    April 2nd, 2014 at 11:36 am

    TY! For the advice on saving my Roses from those black spots!

  4. dotty Says:
    July 1st, 2014 at 5:29 pm

    I purchased 2 rose trees(small miniature roses)(one red rose and the other white) in pots in April. They were beautiful, full of flowers and buds. The next set of blossoms came in tiny and never opened much. They are dry looking with black in the center… I have tried pruning them, am careful not to over water, etc. I think they have a fungus.. What do you suggest?

  5. priscilla fitzgerald Says:
    October 17th, 2014 at 5:14 pm

    should I use dormant oil or lime-sulfurs spray on and around my rosebushes before I mulch them for winter? I have had had some problems with black spot disease.

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