I know from experience how soothing and de-stressful it is to sit for a time in a garden. I do so at every chance I have, especially after work. Here is a great article on just that

Oliver Sacks: The Healing Power of Gardens

And a second article on "forest bathing" or as Japanese call it "shinrin-yoku". No not taking a shower among the trees but just walking through a natural habitat like a forest.

‘Forest Bathing’ Is Great for Your Health. Here’s How to Do It