Opposites, dichotomies, polarities, yin and yang, they're all part of reality. And they're all part of our bodies and minds as well. Much as contemporary culture loves action and accomplishment, we still need both rest and stillness.
And where better to practice stillness than in a garden? You don't have to close your eyes and do something structured called "meditation." Just sit and watch and let thoughts slide away into an awareness of everything around you. A minute, ten minutes, an hour, doesn't matter. Just set aside small spaces of time for paying attention to something outside the human world.