Katya, I know my rose is about 4 months old. We had 100-106 heat waves for a while before the daily rain came ( hurricane seasons ). My rose is still in the same pot and I know it is not fertilizer. Mine has to be be burn or heat stress. So, I moved it to shady area. So far , it has not worsen. But the colour one goes dark then drop off showing half leaves or 2/4 leaves. I hope my diagnosed is correct . I am studying it as I go along for future references for myself.
Here are my pics as it is strong colours than darken then it just drops off to wherever line that goes clean cut.
This is new to me. Ingrid is right not to worry until....
I am guessing about my rose . Trying to acclimate it or seeing where it is best happy.

jin

I meant 1/4 leaves not 2/4...error oops !!
jin

Yes Plumeria some of the times I see what you see too, not worrying anymore. :)

Ingrid: Thank you for that. maybe you wont believe this but right after i read your lines I let go of my worries.

Same thing here, this year it’s way to much rain.

For my garden that is.