A large part of being able to relax outdoors is being able to immerse yourself in plants and nature. Therefore, you want to be able to satisfy all the senses with the choice of plants.
Ornamental grasses like Pennisetum alopecuroides (Chinese fountain grass) will provide structure, height, and beauty to the space. This grass is a lovely evergreen that turns shades of brown through winter. As well as offering beauty, they can add sound to the space with the whispering of the rustling foliage in the wind. Another benefit is that they can soften harsh landscapes which can help to create a soothing space.
Choose a couple of fragrant plants that can enhance the relaxing nature of the yoga garden. Lavender and rosemary are great for this, because the fragrance of this evergreen can help to relax to feel fully immersed in nature. Similarly, jasmine, and chamomile can be a great backdrop for the garden.
Add structure with larger plants such as Acer palmatum (Japanese maple). These are great for many sized gardens and grow well in containers. With many varieties to choose from, there are a whole host of leaf shapes available. The foliage turns incredible shades or red, purple, orange and gold through the year, helping you to be aware of nature and natural changes and cycles in the world.