How do I get rid of a black spot on my roses?

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d of black spot on my roses. Anything I plant gets black spot. It has spread to other flower beds. Roses had been removed several years ago. Black spot still in ground

  6 answers
  • Since it's a fungus, it will live in the damp soil. Here's a link with ways to treat it:

    https://www.todayshomeowner.com/how-to-control-black-spot-fungus-disease-on-roses/

  • Lynn Sorrell Lynn Sorrell on Mar 28, 2019

    It does not live in the soil but in the infected plant matter that is in the soil so you need to remove all fallen leaves/plant matter from soil and burn them or discard bagged well in trash. Removing all infected plant leaves from plants cut them off & treat the same. Then spray remaining plants to prevent further infection. cut back on watering and never water with sprinklers or from hose onto top of plants this further washes all spores onto more plants. just water directly onto soil around base of plant. Check to see if surrounding trees shrubs are blocking sunlight. Bright sun and good air circulation are essential for getting rid of black leaf spot. For killing spores do this------

    There are several good fungicides on the market, several of which claim to be organic. They come in handy bottle sprayers, but if your garden is large, you might want to buy it as a concentrate to mix in your tank sprayer. Neem oil is another alternative for treating black leaf spot. It’s an oil pressed from an evergreen tree. It’s all natural and has shown some remarkable results as an effective garden fungicide. For those of you who prefer Grandma’s solutions to garden problems, try this: Mix one heaping tablespoon of bicarbonate of soda (baking soda) into a gallon of water for your sprayer. Add a dash of horticultural oil or horticultural soap(you can use Dawn dish soap) and Voila! You have a method of treating black leaf spot that works by changing the pH on the leaf surface to one the fungus can’t survive. The oil or soap makes the solution stick and the cost is around four cents a gallon.


    • See 1 previous
    • Lynn Sorrell Lynn Sorrell on Mar 29, 2019

      Blackspot spores will fall to the ground and stay in the leaf matter/mulch at the base of your roses. It is best to remove it, so the area is clean and dries out then remulch then only use good organic clean compost ;Add a source of nitrogen to garden soils before applying wood-derived mulches. Soil microorganisms that decompose organic materials such as wood-based mulches are effective competitors for limited soil nitrogen. This may cause temporary nitrogen deficiencies especially in Roses,annual & perennial plants. Yellowing of leaves often indicates a nitrogen deficiency. Lightly incorporate a source of nitrogen such as bloodmeal, urea or a high nitrogen lawn fertilizer before applying mulch.

      Do not place mulch directly against plant crowns or tree bases. Mulch placed directly in contact with stems or tree trunks may retain excess moisture around the base of the plant that can favor the development of diseases like crown rot. Mulch piled around plants may also serve as lodging for bark and stem eating rodents. Avoid 'volcano' mulching where mulch is piled into a large cone shape against tree trunks.Pull mulch away from the base of the trunk.

      Mulch applied too thickly can cause problems. A wood-derived mulch may undergo high temperature decomposition causing it to dry out. The mulch may then be colonized by fungi that create water repellent conditions throughout the mulch. Water is unable to penetrate the mulch and reach the soil and plants fail to receive adequate moisture. Mulching too deeply can also cause the soil to remain continuously wet contributing to root and stem rot problems in addition to depriving plants of needed oxygen. Apply a mulch layer no more than 1 to 3 inches thick.

      Thoroughly water newly installed wood or bark mulches. Many good quality mulches are stored in large piles that reach high temperatures. When the mulch is spread or bagged, the high-temperature tolerant microorganisms that inhabit the mulch die as the mulch cools. If the mulch is allowed to dry out or remain dry, nuisance fungi can colonize the mulch and create a water-repellent surface.



  • Joy30150932 Joy30150932 on Mar 28, 2019

    Lynn has given you some really good advice so there is no need to add more.

  • Ann Ann on Mar 29, 2019

    Good advice from Lynn except, sometimes you have to dig rosesup. I had this happen to me and I was told to clean roses roots . I dug up roses put them in soda and dawn water while cleanedup area where they were. I took out 4 inches of soil and made sure area was clean . The put in new soil and replanted roses. The mulch I used was what caused my problem. Be very careful of the mulch you use. I had help with getting all this done. Be careful of leaves and other like matter collecting in rose beds.



  • DesertRose DesertRose on Mar 30, 2019

    roses need to be where they receive direct sunlight most the day to prevent fungus. Be sure they have the sunlight, water only from the base and keep all dead organic matter removed. Also, I cut off the leaves/stems with the black fungus and bag them to the trash can to prevent further infestation. Hope this helps, lots of good info already but wanted to add this. Hope it helps.