So, where does Grandma work? In episode 1 of Tsuritama Grandma Keito has a new job and she moves to Enoshima with Yuki.  She now works here (time mark 7:11):



The old-timey font defeats me, and I can't read it.  The best I can do is Gnolhima Samuel Cocting Garden. She is obviously a horticulturist of some sort. What is the actual name of the place?  I'm pretty sure "Samuel" and "Garden" are right.
According to Tsuritama Wikipedia, the store Grandma Keito works at is the
Samuel Cocking Garden


  Kate (ケイト Keito)
  
  Yuki's grandmother. She's French, and has a warm
  and cheerful personality. She allowed Haru to live with her and Yuki.
  She often gives Haru advice concerning his relationship with Yuki and
  human social interactions. She works at the Samuel Cocking Garden in
  Enoshima.


This garden, also known as the Enoshima Tropical Plants Garden, is an actual botanical garden in Enoshima, Japan