might be chlorosis.

try spraying the foliage with iron chelate

Yes, that definitely sounds like iron chlorosis, especially since you said it started after the heavy rains. Too much water can keep a plant from being able to use whatever iron is available. Treat with iron chelate foliar spray for a quick fix and a couple weeks later (and annually in the spring) incorporate some around the root system for longer lasting results. Let the soil dry as much as possible between watering, without stressing the plant, until it recovers. It may bounce back and do fine or you may need to replace it. Some plants, like hibiscus, can have a hard time using the iron in our soil if they prefer an acid soil.

Thanks for the info! I've got two that have been suffering likewise. I really had no idea what was going on till I saw this thread!