In the assemblies of the enlightened ones there have been many cases of mastering the Way bringing forth the heart of plants and trees; this is what awakening the mind for enlightenment is like. The fifth patriarch of Zen was once a pine-planting wayfarer; Rinzai worked on planting cedars and pines on Mount Obaku. . . . Working with plants, trees, fences and walls, if they practice sincerely they will attain enlightenment.
Source: Awakening the Unsurpassed Mind, #31
Contributed by: Zaady