All my disease resistant phlox have been yellowing from underneath. I sprayed with Greencure fungicide which is supposed to be better than the homemade remedy but see photo Is this a fungus or something else?

I'm in the Dallas, Texas area and planted some small John Fanick phlox in April. It seems to be healthy, but it hasn't grown any taller since I planted it. One of them bloomed briefly last week, but at 8 inches tall compared to the 36 it's supposed to be I'm thinking somewhere I've gone wrong. They're in a location that gets sun for a little more than half a day. They are mulched, is that bad? I haven't "fed" them anything at all, but they are in amended soil.

I apologize I believe I posted this in the wrong place. I got an answer on another board. Thanks, Franny

the whole flower bed has only been there for maybe 3.5 weeks. ==>>> large transplant.. fertd at planting ... transplant shock ... and a rather minor type .. but for one stalk.. that may have been damaged in shipping and or planting .... one ugly stalk in the whole bunch .. the rest looks fine ... cut it down.. out of sight.. out of mind ... you might have been a bit late in planting large stock .. here in MI .. we are in week 4 of drought.. week two of supreme heat ... if i had that same plant.. it would be near total collapse... perhaps you ought to be focusing on your successes.. rather than this ... alos.. imo.. try to avoid use of fert when transplanting .. that itself is enough stress.. somehow burning off the roots would not be a plus .... and food doesnt offset stress .. no matter what grandma told you ... please add your location on your members page.. ken