Diagnosis? Black Edged Leaves
I've recently begun paying much closer attention to all of my plants and am trying to track down causes for a lot of issues I've previously just let slide.
This rose tree (no idea what kind, came from my parents without tags) is under cool white fluorescents in ~65 degree temperatures with additional southeast sun from a window. I've recently sprayed it with insect and fungicidal soaps (maybe 2 weeks ago). I am fertilizing with 1 tsp Foliage Pro per gallon (9-3-6) and I make sure to check moisture levels before watering. The fertilization is a recent development, up until maybe a month ago I hadn't fertilized it at all.
I can't figure out why it has these black margins on the leaves - it was doing very well all winter and then suddenly I got a pretty significant number of dry yellow leaves and now maybe 50% of the green ones are developing this black border. From Plant Diagnosis
Does anyone have any ideas? I tried to search for an answer but most everything came back with "black spot" which I don't believe this is.