Black spot disease showing on rose bush leaves

Black Spot on Roses

Black Spot on Roses Treat and Prevent

Black spot disease showing on rose bush leavesYou can hardly find a home garden without rose plants. Everyone loves to grow roses in the garden. With great care and attention, you will be able to easily maintain your rose plants. One of the most serious diseases that you find on the rose leaves is the black spot on roses. You should treat these black spots on the rose leaves to keep the rose plant healthy.

What is Rose Black Spot?

The black spots on the leaves of the rose plant are a nasty fungus. The black spot is known as Diplocarpon rosae is a fungal disease. As the name suggests, you will see black spots all over the leaves of the rose bush. If you do not treat the black spots on the bushes, then it will make the rose bushes defoliate.

What Causes Black Spot on Roses?

There are many home gardeners who wonder how the rose gets affected by the black spot fungus. One thing you need to understand is that roses and black spots go hand in hand. If you find the rose plants have very few black spots, then this can be tolerated to a certain extent without causing major damage to the plants. If your rose plant has huge amounts of black spots, then they would easily cause the leaves to defoliate.

The dark brown to black leaf spots seen on the upper leaves of the rose is the work of the fungus and this would finally end up turning the leaves to yellow colour and then drop. The dark black colour and the fringed edges help you to easily identify the black spots from other leaf spots. You might also see reddish–purple raised spots on the cane of the rose. The real cause of the black spots on the roses is the water splash from the ground soil, fungal spores splashing up on to the rose leaves and spreading, this is more prevalent in high rainfall areas of Australia and overhead watering will also cause black spot on roses. The fungus thrives in warm and humid conditions and is an ideal condition for the fungus to germinate and grow.

Black Spot Fungus on Roses Treatment

If you find black spots on the leaves and branches of your rose plant, then you should prune away the infected leaves and canes. You should gather up all the fallen leaves of the plant. It is not ideal for you to collect the leaves and use it in the compost. It is better to collect the damaged leaves and throw it away. It is also a good idea to prune off all the stem lesions during spring time before the leaves start to show up. Then lay down a complete new layer of mulch in early spring to prevent blackspot on roses. This will help in delaying the arrival of black spots.

Black Spot Best Prevention

  • Prune your rose bushes properly by opening up the centre of the plant is the biggest prevention. Here is how.

Spraying Fungicides

After you have pruned off all the affected leaves and the stem, now it is time for you to treat the rose plants with a chemical fungicide.

  • You can get any fungicide available in the market and nursery then spray it over the entire plant.
  • Make sure that you spray it on the upper and lower leaves as well as the stems of the rose plant.
  • This will prevent the fungus to germinate and grow on your rose plant. Use this regularly during summer.
  • You can also use a number of organic options but I use Lime Sulfur after pruning the rose.

Using Baking Soda & Milk as Natural Remedies 

As soon as you spot a few black spots on your rose leaves, you can use a natural remedy using baking soda solution to prevent it from growing on the entire plant. It will work very well as a preventive measure and as baking soda contains salts, you should never use it in higher concentrations. This can damage your plant.

  • Use 2 to 4 teaspoons of baking soda and mix it with 2 teaspoons of organic horticultural oil.
  • Dissolve this mixture in half a plastic bucket of water.
  • Do not spray this mixture of baking soda and organic horticultural oil during the heat of the day when the suns out because the oil in the mixture will attract the hot sun rays, in turn, this will burn the leaves on the roses.

If you prune your roses properly you are sure not to get black spot on your roses its as simple as that!




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