Black Spot

May 28, 2014

Black Spot Fungus

Black Spot on roses is a huge disappointment to any rose lover. Prized for their beauty, ugly spots on rose plants detract considerably from your enjoyment. If the weather is particularly wet or warm and humid, Black Spot, a fungal disease, can easily find its way to your rose bushes. Leaves will yellow and fall off, resulting in a weaker plant vulnerable to other diseases. Rose problems can have long-lasting effects even determining how well the plant survives the winter. Black Spot can quickly spread between plants if it isn’t taken care of when it appears.  


There are some easy tips for preventing Black Spot


  • Hygiene is job one for taking care of roses. Don’t allow leaves or other debris to lie around on the ground under the plant, as it makes a nice environment for fungus to establish itself. Fall clean up is as important as any other time since fungal spores can overwinter in the soil.


  • Roses are meant for sun. This means 6 to 8 hours each day including morning sun which can dry out the plants quickly when they’re covered with morning dew. Black Spot isn’t fond of sun!


  • Planning for a nice amount of space around each plant will go a long way to aid in the overall health of your rose bush 3 or 4 ft. between plants helps immeasurably. Air circulation is a key part of keeping leaves and blooms dry.


  • Well-draining soil is essential. Amend your planting area with rich compost. This will help a great deal whether your soil is sandy or clay.


  • Use a soaker hose to water roses. This sends water deep into the soil where roots are and not all over the leaves, flowers and buds as a sprinkler or regular garden hose will do. The more water you keep off the plant itself, the better. If you must use a sprinkler or hose, do it in the morning so roses have a chance to dry out during the day. Sprinklers can also cause fungal spores to be picked up by water splatter and deposited on other plants. That’s another good reason to use soaker hoses.


  • Pruning is important too. Taking off broken or unhealthy branches to strengthen the plant, in general, making it less susceptible to diseases. Again, this improves air circulation by lessening the amount of dampness that stays on the plant. Prune regularly. Once a year may not be enough.



What if my rose already has Black Spot?


When you notice yellowing leaves and black spots forming on the tops of leaves (usually the ones lowest on the plant), you’ll want to treat for Black Spot right away.

  • Remove any leaf or branch that looks unhealthy. Also, make sure to clean up around the bottom of the plant where yellowed leaves have fallen.


  • Spray the plant every week with a fungicide. As with anything concerning roses, there are many cures and recipes mentioned on the internet for preventing or treating Black Spot which you may want to investigate.

  Printable version of Black Spot Fungus