Power plant is such a plant, which has a Power to move. Usually, power plants are very dangerous (see trifids for example), old and unclear (with an except for new clear power plants). Power plants pull their roots from a ground, and then you can see them even walking in streets.
Oh, did you know that George W. Bush is the most famous example of power plant?
As you know, different types of power exist in the universe that can be used for plant motion. A few experimental examples: