Because of the excessive rain, a number of my plants (not the irises) have chlorosis ... I think. I have read that one needs to apply chellated iron. A French is a quick easy fix. But really, everything I have read says a soil application is best for long term results. Have never used before, so I have the following questions. Can the quick easy fix be done at the same time as the longer fix?

If the chlorosis is due to heavy spring rains, it is likely only a temporary condition, and should correct itself after the soils have had some time to drain and re-aerate.

I'm not sure what a "French" is?

if you need a quick fix chelated iron can be sprayed foliarly. the pelleted form for longer lasting methods doesn't work as quickly, though.

however, i really like and use 'dr. green' liquid, but it leaves an unsightly black mess on the leaves if sprayed. i haven't been able to find 'dr. green ' of late and have resorted to 'monterey dr. iron' in pellet form. (unfortunately, i threw away the last gallon of 'dr. green' so i don't know who the manufacturer is, and the nursery where i purchased it, is no longer open.☹️

there are a few liquid products out there, i don't know if they can be sprayed. but i am sure they can be mixed, and poured around the plants.

An application of Ironite would be a good start, IMHO. Easy to apply granule, but follow the label closely - too much can cause temporary phytotoxicity.

Another good source of iron would be Azomite, a ancient seabed mineral with many other micronutrients beside iron. Soil tests usually show a more or less, a deficiency in magnesium too, along with a iron deficit. Usually clay soils ( which are mostly commonplace in the SE U.S) have enough of the micro nutrients, but a very low p.H can lock up iron too. You might get your soil's p,H tested too.

Many times, in very acid soils, a timely application of dolomite lime will correct a chlorotic issue, and a magnesium deficiency too.