This is the second time Jon Hamm is interviewed on Between Two Ferns. The first time (in 2010) the chyron says "Jon Ham, Actor, The Mad Men "

There are actually many types of ferns in this film. Most often Zach is with an athyrium filix-femina, the lady fern, or the highly popular Boston fern, nephrolepis exaltata.

Zach enters a bar called "The Lonely Horse", and on the TV inside is P. F. Tompkins. This is possibly a reference to BoJack Horseman, on which P. F. Tompkins plays Mr. Peanutbutter.