Flexible yet indomitable

You want to be flexible. Not like water, which will flow around anything, but will be stopped by a simple dam, be pumped away, forced into a new path, evaporate, or simply sink into oblivion.
You want to be indomitable. Not like a rock, which is hard and strong, but once cracked, will never heal itself.
No, you want to be flexible, yet indomitable. Like a tree.
A tree will grow past any obstacles, cracking concrete, breaking through rock. It will stand against hurricanes and floods, shaking, bending, but resuming its growth once the storm passes.