While roses can take pride of place in your garden, you can find at times the leaves begin to take on a mottled appearance and are full of dark spots.
Once you understand what it is, you can see the name of the black spot is very appropriate for the disease.
The fungal disease can cover all the foliage of your plants, and if you don’t treat it appropriately, it can cause your plants to lose all their vegetation.
In our guide, you can find out what causes black spots on your leaves, and what is the best black spot on roses treatment. (Read How Many Types Of Roses Are There)
What Causes Black Spot in Roses?
The fungal diseases that causes these black spots on your roses is called Diplocarpon Rosae, although it is common for rose leaves to have black spots that are not much of a threat. Still, severe cases can cause defoliation in your pride plants.
The fungus causes the spots that range from dark brown to black and form on the upper leaves. After a time, these then turn yellow and begin dropping. It is easy to distinguish these diseases as you can see fringed edges on the outer portions of the black spots.
You may also see the fungus affecting young canes where black to purple blisters begin to form. Also, there may be red spotting on your flowers. One effect of this apart from the visible aspect are fewer flower buds that have no leaves.
You tend to see this fungus growing in warm, humid conditions.
How Do You Get Rid of Black Spot on Rose Bushes?
Prevention for black spot is better than the cure, although there are some things you should do at the first signs of the disease.
- Remove any infected leaves from your rose bushes to limit the spread of the disease
- Prune any canes that have an infection and discard these away from your plants
- Avoid overhead watering and wetting the foliage
- If there are any fallen leaves, rake these up and dispose of them carefully
- Spray the roses with fungicide frequently during the growing season. It is better to use a liquid variant rather than powder.
How Do you Treat Black Spot on Roses Naturally?
If you have a rose, black spot can be killed yet the marks will remain for a while, if not until that leaf falls and a new one grows.
You tend to find that early spring is the best time to begin your prevention.
While you can find many fungicides available, some gardeners wish to tackle this black spot disease using natural methods. You can use any of the following as treatments:
- Hydrogen Dioxide
- Lime Sulfur
- Neem Oil
- Potassium Bicarbonate
- Copper products
One thing you do need to be careful of when spraying these are the rose leaves. They are waxy, and you will need a spreader in your spray bottle for optimum coverage.
A more accessible organic treatment for black spot can be baking soda. How this works is by changing the pH levels on the surface of the leaves. As a result, it can be more challenging for black spot to infect your plants. (Read How Many Types Of Roses Are There)
All you need to do is one or two tablespoons of baking soda into a gallon of freshwater. In this, add a drop or two of liquid dish detergent (bleach-free). Add this to your spray and spray both the upper and lower parts of your leaves.
Apply this treatment for black spot on roses once per week, or again if you have any rainfall.
How Do You Treat Black Spot on Roses in America?
We have seen it is easier to prevent roses with black spots on leaves than it is to cure it.
Here are all the things you can do to help prevent black spot infections on a rose plant.
Prevention of Black Spot
The moist conditions can encourage the spread, so in early spring, you should be starting your treatment. Either a good fungicide or a natural mix will help.
You continue this every seven to 14 days until the conditions are not ideal for the disease to take hold, and any new unfurling leaves are protected. (Read Pruning Arborvitae)
Limiting Black Spot
You do need to act fast because a black spots can affect more than your roses. You may need a good fungicide to limit the spread. Follow the same weekly patterns as above.
Protection Against Black Spot
Healthy rose plant tissue needs protection against infection. A good fungicide can help stop these new parts of your rose bushes from becoming infected.
Here are some other things you can do to help stop black spots ruining all your hard work. (Learn How To Seal A Chipmunk Hole)
- Maintain good air circulation: Be sure you don’t have any overcrowded rose plants. If your rose plants are too close together, you lose circulation, and this delivers the ideal conditions for the black spot disease to thrive. With space, your plants can dry much faster.
- Watering Times: Never water at night and always water early in the morning. If you water later in the day, the water won’t dry off, and humidity increases.
- Don’t Water from Overhead: Use either a drip feeder or at ground level by the rose roots. The drier your rose leaves, the less chance they have of black spot.
- Keep Clean: Always remove any dead leaves or stems. You may need to prune these. It is also another reason not to overcrowd as you have better access. Clear away debris and make sure to wipe your pruners with alcohol or household cleaner.
Once you begin to keep a clean and sanitary garden, it is one of the best steps you can take to prevent black spot on your rose plants. Also, if you expect it, then you can be ready to fight it on the first signs of its appearance.
It may arrive unexpected, yet with the above information, your rose plants have the best chance of growing healthy.
Read more: Fun facts about sunflowers