The root ball was so ingrown that its not able to break out of the original pot shape.
That's way too much water. But water may not be getting into the center of the root ball so not enough water.
If its growing out of the rootball normally, watering 5 days a week will be too much. But water doesn't always manage to penetrate rootbound root balls.
The problem is that watering too much and watering too little look the same. As its been in the ground for only three weeks, I would gently dig it up and check to see what's up. It should have started making some progress on breaking out of the root ball by now so dig away from the plant.
If you discover plenty of escaping roots, water less. If the roots are still in a tight ball, try to loosen and gently pull them apart and replant. Than water less.