Noticing a small black spot on the leaves of your roses may frighten you at first. But the treatment of this disease is no different from the treatment of any other flower illness. There are three keys to it: disinfection, cutting damaged parts off, and proper aftercare. For experienced gardeners, such disease is unpleasant but not fatal.

Of course, roses require a lot of attention. Not in vain, they are considered one of the most demanding plants, aside from orchids. And when you see black spots on rose bush leaves, well, that may be as frustrating as frightening. We should say in advance: preventing this disease is much easier than treating it. But you shouldn’t worry! Though the treatment may turn into a full war, you still have chances to win it.

Fortunately, if you take some preventive actions, you can easily avoid the sight of your rose’s leaves turning yellow with black spots. And gladly, these actions are not that difficult to do. Now, let’s find out what exactly this disease is, the reasons for it and how to save your roses from it!

What are these black spots?

These black spots are the result of fungal disease. It has two life stages: 

  • asexual, which is known as Marssonina rosae. You can say it is Marssonina rosae when your roses have small black spots on leaves. But they are usually very small (less than a millimeter) and have no other color in or around them.
  • sexual, which is also the most common: Diplocarpon rosae. This is also the final stage. That’s when the spots get larger, so you can even distinguish different colors in them. Usually, brown, white and yellow. 

The disease starts from the bottom leaves. The first dots appear on the edges of the leaf and slowly progress to the cane and stem. The illness may affect even stems and buds. So, you will see large purple blisters and spots. That’s why you have to treat your rose bush leaves as soon as you have seen the black spots on them.  

The further the disease goes, the more yellow your leaves get. In the end, they simply rot and fall off. 

How to guess that it is Diplocarpon rosae and not another fungus?

You can guess it’s Diplocarpon by its spots. Commonly, these are circular dots with black fringed edges. Depending on the stage of the disease, the center of it may be brownish if it’s only beginning, or white, if it is the final stage.  

Anyway, roses with black spots on leaves require immediate treatment. But you have to know the reasons for it to treat them right.

Reasons for black spot disease

Well, the reasons for a black spot disease appearing on the leaves of your roses are common to all fungal diseases. There are several of them:

Excess moisture. Most funguses love humidity and cool weather. Diplocarpon is one of such funguses, and that’s why your roses are at great risk at the beginning of spring. A lot of inexperienced gardeners think that watering their plants a lot will not only be safe, but useful. Unfortunately, this is the main reason for black spot disease to affect roses

Excess fertilizing is another common mistake among beginners. Feeding your roses with too much fertilizer can be as bad as giving none at all. Feeding your flowers with inappropriate fertilizer may be harmful too. The excess amount of useful minerals and vitamins will simply cause the rotting of the plants. Or it may weaken the resistance of your roses, making them a perfect victim for black spot disease.

Stuffiness of the air. The third reason is the lack of fresh air for your roses. Too hot and stuffy air has no benefits for flowers at all, especially roses. These flowers are like sunny and well-ventilated places, with a constant flow of fresh air. Fresh air is crucial when you are searching for a cure for the black spot on your roses.

As you can guess, these three reasons working all together can do great harm to your roses. But, actually, they are the key ones in treating black spots on roses

Rose black spot disease treatment

Treatment of black spot on roses is a long and difficult process, but still possible to bring you good results. First of all, you should remember the main key to every good treatment: it is a combination of specialized treatment and domestic one.

  • Professional treatment implies the usage of specific medications and drugs. In this case, you may use fungicides, like neem oil, or products that include copper and sulfur. These are sure to assist in a long fight against a fungus disease.
  • Domestic. If using a specialized treatment seems not enough, there are a lot of home recipes from proficient gardeners that will make a great company for professional products. For instance, you can mix 2 tablespoons of soda in 4L of water. Spray the foliage with it once a day, especially after the rain.

 So,  the best treatment of rose with black spot illness includes:

  1. Using only disinfected shears and other gardening tools. Before the cutting, wash your hands and wear gloves.
  2. Cutting off all the damaged leaves. Don’t use them as soil, as the fungus may jump to other flowers. 
  3. Transplantation of the diseased flower separately from other plants. In this way, you will prevent a massive infection. This is an emergency point, which should be done, only if your rose has a harsh stage of illness.
  4. Applying specialized professional products. Treating black spot disease on roses is impossible without specialized products.
  5. Provide your plants with enough sunlight and fresh air. Also, keep in mind that the place shouldn’t be too wet. 
  6. Don’t over-water or -feed your plant. Pay attention to feeding it right, as it is key for the cure of black spot on roses.

How to prevent rosesblack spot disease

Of course, preventing the disease is much better than fighting with its results. So, let’s find out what are the keys to your rose garden wellbeing!

Right watering. Fungus disease usually affects roses at the beginning of spring, when in the day the weather is warm, but the nights are still cold. That’s why it is so important to not overwater your plants, as wet roots will definitely freeze and rot. Also, watch out for the foliage to stay dry, when you water the plant. Most roses have black spots on leaves for this reason. Water your plants in the morning, so the drops have some time to dry by the night.

Provide the plants with nice air circulation. The constant stream of fresh air plays a great part in your roses’ health and resistance to illnesses. You can do it not only by planting them wisely, to leave some interval between the plants. But, also weed out the ground, to let the air pass between the roots. Fresh air is also essential in the treatment of black spot illness on roses.

Give your roses sunlight. Roses are known to like sunny and light places. Thereby, when planting your flowers, consider some nice place, with enough light. But watch out to plant it under the shadow. Roses don’t like straight sun rays, so avoid them from getting there, or they will be burned. 

All in all, though black spot disease on roses is quite an unpleasant thing to face, there’s a cure for it. Anyway, mind that preventing the illness is much easier and better than even the best treatment. 


  • Can roses recover from black spot disease?

Unfortunately, the black spot is the hardest illness for roses to overcome. Even after a cure, most plants don’t live for too long. Especially if the treatment was given too late. In such cases, there is 90% the plant is going to die. 

  • Should I remove rose leaves with black spots?

Of course, you should. Actually, you have to do it as soon as you have noticed it, to slow down the spread of the illness.

  • When should you spray roses for black spots?

To avert the black spots disease, you have to apply the spray to the flower every two weeks from the start of the growing season.

  • Is vinegar bad for roses?

While a lot of gardeners recommend using a bit of vinegar in curing the black spot, you should do it very carefully. Using too much of it will simply kill your roses. 


Read also:

Misconceptions When Selecting The Prettiest Rose

September 03, 2021 — Alexandr Oleynik