I've never been able to find out anything about The Cactus Garden! Until...I was reading the book "Building Hoover Dam: an Oral History of the Great Depression". There was a sentence that referred to The Cactus Garden, owned by Paul Warner. A page of the book, referring to several of the "bootlegging establishments", is printed on Over50Vegas's webpage:

https://over50vegas.com/200_Fremont___Fremont_Hotel_Casino.html