In Redding California there is a beautiful Arboretum. I went there some ago and really enjoyed it. It is considered part of Turtle Bay Exploration Park. They have different zones in the Arboretum and grow flowers and plants that thrive in these different zones. I took a lot of pictures when I was there wandering around. They also allow the local college students to gather plant clippings for various academic reasons such plant ID practice and testing. https://www.turtlebay.org/gardens/