I think I also first found him from his "guerrilla gardening" work in Oakland. I think it was in a median, planting native species on a barren strip of dirt. Something of that nature.
His backstory is really one-of-a-kind. If I recall correctly, he got really into botany because he worked for Union Pacific railroad, and while stopping in a city, would go to the library and checkout different botany books.
I believe I discovered him through that same video! I now tell everyone I know about guerilla gardening lol, haven't got the know-how to do it myself quite yet though. Soon enough.