Friday, May 21, 2010

I think something is killing my roses. Can you help?

The leaves on my roses are turning yellow and they are getting black spots on them. They just don't look very healthy at all. What should I do for them?

I think something is killing my roses. Can you help?
From what you are describing it sounds like nitrogen deficiency...check the site below which has a picture. If it looks like that you can do a google search for additional products to add nitrogen including blood meal (you can get it at most hardware/plant stores).





Update: to clarify mdcarper's post regarding black spot disease...here is a site for that...http://www.ext.vt.edu/pubs/plantdiseasef...


I would only suspect black spot if you are in an area that has had a lot rain or humidity this spring. If it has been dry (normal amounts of rain) and you have this I would stick with nitrogen deficiency. The site I first listed shows both so you can do a comparison.
Reply:This sounds like a fungal disease called black spot. You can get chemicals to spray on (Rose Clear is a good one). Remove infected leaves and burn them. When the leaves fall in the Autumn, pick them up and burn them. The fungal spores lay dormant in the soil over the Winter and will infect the plant again next year. You will need to be vigilant and treat it immediately you see any signs. Black Spot is not easy to eradicate but can be kept under control.
Reply:get a spray that kills aphids and helps control the mold thats causing the branches to blacken is a disease caused by over watering and stuff.
Reply:it's black spot! just gently pull off all the leaves in question then add some of this stuff to prevent it from happening again...follow the link! can be found at walmart or lowes!
Reply:You named the disease in your question. The diseases is black spot. Copper is the best treatment. Spray every 7-10 days. The leaves with the spots will eventually fall off, but the copper will prevent the fungus from spreading. Your rose will eventually sprout new leaves from the axillary buds and your rose will be fine, but the sooner you treat the better.





Update: Blackberry, I disagree with the higher than average rain/humidity comment. We grow 1.7 million roses on our nursery a year, and we have had black spot this year. We had 0.5 inche of rain in May, and we still can locate the issue. I have never seen distinctive black spots from lack of nitrogen. If anything, lack of nitrogen will cause chlorosis and necrotic brown/tan spots. Black spots with characteristic tip chlorosis is a definite sign of black spot. P.S. I went to Tech and had Mary Hansen as my plant pathology teacher.....I'm quite familiar


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