GREATER MILWAUKEE ROSE SOCIETY
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Growing Great Roses
Problems
To avoid problems, choose varieties that are not prone to problems.  (See Recommended Rose Listing)  Keep your roses healthy from the beginning.  Roses, like us, do best when they are healthy.  Weaken the bush, and you will have more problems.

IF YOU CHOOSE TO USE CHEMICAL SPRAYS TO HELP CONTAIN OR PREVENT DISEASE AND INSECT PROBLEMS, BE SURE TO CHOOSE THE CORRECT PRODUCT FOR THE PROBLEM.  READ AND FOLLOW THE DIRECTIONS FOR AMOUNTS, SPRAY CYCLES AND PROTECTION.  REMEMBER, THESE ARE CHEMICALS WITH VARYING DEGREES OF TOXICITY. 

  • Be sure your roses are well hydrated.
  • Spray only when the wind is calm.
  • Spray only when the temperature is below 85 degrees.
  • Protect yourself with a good respirator system.
  • Wear protective clothing. 
  • Dispose of unused spray appropriately.
  • Learn your level of tolerance for the problem.
  • Alternate spray products.  This helps break the infection cycle.

Diseases
There are two common diseases in our area:  powdery mildew and blackspot.

Powdery mildew: 
  • occurs during our warm days/cool nights
  • spores are airborne
  • appears on new growth at the top of the rose
  • turns the foliage a powdery gray.
  • wrinkles and distorts this growth. 

Treatment:
Keep bushes hydrated
Use anti-desiccant to prevent infection
Spray with proper fungicide if infected.

Blackspot:
  • is weather dependent
  • spores inhabit soil
  • two week interval between infection and sighting of infection.

Treatment:
Remove all dead or diseased leaves from the soil
Remove the lowest 8-10” of leaves from canes
Water at the soil level and try not to splash up into the bush.
Use appropriate fungicides; alternate products
This page was most recently updated on 3/20/2013