yellow leaves may simplyt mean trauma from being transplanted. Citrus is very finicky about over watering, be careful where you plant and know that a hard freeze can kill these yummy trees so put in a protected place. Once established they are pretty tough. After the fruit is picked it is the only time to trim and shape your tree, as they bloom right after harvest. They also produce on new growth, so at least trim the ends each spring.

My trees are at the breaking point with tons of fruit in shades of green and yellow and new growth already popping out.

Enjoy