The Asian Style uses water, rocks and evergreens with a variety of plants to create distinctive perspectives. You might also consider adding a traditional Japanese Zen garden.
Fragrant plants contribute to meditation. Garden colors determine moods. Plants affect your physical and mental well-being. I have used plants with success in meditation designed gardens. Water and stillness are big elements in a meditation garden. The simpler the better, do not use to many different plant colors or textures.