If I were you, I would flush them out with lots of clean fresh water, I assume you are in soil?
5 gallon pots use about 15 gallons of water the rule I use when I have had over fert problems or salt build up, is flush with 3 times water to pot size.
give them a week or two don't feed just let em dry out a bit before you water not super dry just enough to let them get some life back that you know looks right.
best of luck.