Don't push personal growth; remove factors limiting that growth. I've found if you push someone toward a goal your likely to encounter a push back, or resistance. Clear the path toward that goal and encourage the individual to move in that direction! Promote the good they do and ignore the bad.
People who try to break a bad habit often come up against limits to growth. This is where positive reinforcement is the key. Those positive feelings uplifts them and creates a reinforcing spiral of improved behavior, creating a uplifting atmosphere and further improvement. Nothing promotes personal growth like the glow of achievement and the recognition of attaining that goal. It's the way to conquer limiting beliefs, which is a major barrier to growth.
If you desire to be a leader who develops leaders, understand the above principle and live it. It separates the positional manager from the true leadership candidate. I've also found it to be the most difficult to master. But then, no one said it was going to be easy...Just worth it!