Did you know that the town of San Diego, California was once a desert landscape? Meet Katherine Olivia Sessions: graduate of the University of California with a degree in science, former school teacher, lover of trees. Looking to change her landscape, she asked gardeners all over the world to find out what would grow and they sent her seeds. She started a nursery and soon people were buying plants from her for their houses. Because of one woman, San Diego has a lush and beautiful city park named Balboa Park.