Just fertilize. You will need to fertilize much more frequently with container citrus that are in well draining potting medium. Most folks on this forum like to use DynaGro's Foliage Pro 1/2 strength with every watering. Limes and lemons seem to need more fertilizing than other citrus in my experience. Especially Improved Meyer lemons, and I think this is due to their heavy fruit set. Patty S.

Silva- My trees look just like yours lately... I am in central Florida so took soil samples to UF 8n January. We were in a drought then. Numbers were ok. Few leaf miners but that is no big deal. Then about May? the trees starting looking poor. Much rain. Over the summer we have had 2-6" almost daily. On August 20th we had the total amount of yearly rain already. Took another sample of soil in and times/fertilized. UF says the huge amount of rain is washing nutrients from the soil throughout our region. The trees are not really 'thirsty' so even when fertilizer is applied it is not taken up because ground is always wet. Then that days rain ...and the next... and so on... wash away the nutrients. Everyone zI know is having same problem. Scary because I don't want our wells contaminated with fertilizer salts.

regardless of where you live.. didnt fall start last week??? and it was recently transplanted ... and its a largish plant ... its stressed ... and finally.. its a deciduous tree ... the stresses are making it shut down a bit early ... i am presuming this is a eastern redbud.. Cercis canadensis ....of which i am familiar... if not.. then my answer might change .... i only mean to point out that your use of a common name can lead to confusion .... so use of the latin name would make it specific .... one of the reasons trees are planted dormant ... is that you dont have leaves to worry about on deciduous trees .... or they are dormant on evergreen plants .... either way.. you usually just dont have to look at something like this.. and then worry ... anyway.. just water deeply and properly with near drying before repeating ..... and see what happens .... see link on watering ... since it deciduous.. there is no use spraying anything on leaves that are going to fall off this time of year ... imo ... ken https://sites.google.com/site/tnarboretum/Home/planting-a-tree-or-shrub

Generally, advice based on research is to not amend planting holes, especially in clay soils. Water flows into amended soils more easily than the surrounding soil, but doesn’t flow out into the surrounding tight clay soil, creating a bathtub effect where the roots are overly wet. If you are going to amend, do the whole bed at once so water can flow sideways. Check to see how wet the roots are. If it is really soggy, remove the plant, partly fill the hole and replace the plant with the rootball about a third to half above the natural soil surface. Mound soil up around it to completely cover the roots and then mulch. IME panicled hydrangeas prefer things much less wet than either big leafed or smooth hydrangeas, though they do need adequate watering when getting established just like any other new planting. As others have said, you actually need to get in there to feel how wet the soil is several inches down to know whether it is too wet or too dry. You want it to be moist, not soggy or dry.