No plant is drought tolerant when first planted. You need to water them every day if it doesn't rain. The term "drought tolerant" only applies to plants once they are well established. In actual fact, crotons aren't very drought tolerant even when they get big and well rooted.
Soil here in Florida dries out very quickly, so you also need to mulch around them with a good thick layer of wood chip mulch, leaves or pine needles - something to shade the soil and help keep it cooler to retain moisture.
