Why do some of my rose bushes have blooms that turn black aroundthe edges and fail to finish opening?

i have other varieties on the same yard that are blooming beautifully,full,red and very fragrant.
Why do some of my rose bushes have blooms that turn black aroundthe edges and fail to finish opening?
do you see aphids? Aphids will eat the tops of the young buds and cause them to fail. Also big weather swings - hot to cold can do that.
Reply:Ah the rose, no other plant hosts as many pests and diseases.



Your roses could have a fungus called Botrytis or Blight. The healthy roses just happen to have a higher immunity to the disease. Or, without knowing what zone you live in, it could possibly be cold damage. When the rose blossoms are exposed to freezing temps, especially at night, that causes the flowers to stop opening and turn black or rot.



I would cut off the damaged flowers and I would take the time to disinfect the pruners with rubbing alcohol between each cut. That way, if it is a fungus, you wont spread it to other plants.