Reason for discolored leaves in kengaizukuri style chrysanthemum

[kekoa]

I’m training several “Firefall” chrysanthemums kengaizukuri style (large cascades) outdoors under mild shade in zone 10. I water them regularly at the same frequency as some new Nippon daisies but I’m noticing that the oldest, inner leaves along the main stem are presenting an unusual-to-me discoloration. I noticed that these inner, discolored leaves also take on a curved shape that’s different from the healthy, green leaves.
Any ideas as to what might be happening?

 

[nuttiest]

potash fertilizer or availability

 

[kekoa]

I have been feeding them a 20-20-20 chemical fertilizer but maybe I could augment with something with more potassium…

 

[nuttiest]

just leach the soil and see what happens, likely magnesium too high, ph too low, etc.

 

[kekoa]

thanks for the feedback!