The Mighty Redwood is Arguably the best plant in the game. This will double Woodrow's life gauge by two, and fill it up. Woodrow will also be given a powerful sword made out of resin that can take out enemies with ease.
There is only one of these throughout the entire game, and it is growing our of the center of the Treant Temple. It loks very similar to a real Redwood Tree. There is a fountain surrounding it's roots, which is flowing with it's resins.