I am vegan and had been really interested in trying this place out.
I was disappointed really.
I visited Seerose twice just to make sure it was not just a bad day. First time no help was offered with what the vegan choices could be. Second time choices were mentioned but "not available at this time". Then I was given two choices as "this and this" which I could derive for myself as some kind of grain dish, and salad. The counter server seemed irritated that I would even ask and quickly went on to another customer, ignoring me; had I wanted to try the dish. Both times I walked out hungry and frustrated, without even wanting to order even a drink.
The menu is very ambitious when mentioning "Dabei haben wir immer mindestens zwei Gerichte für vegane Gäste auf der Tageskarte" (There are at least two meal choices for vegan guests on our daily menu")
Stylistically, and not trying to be mean; Seerose looks like a tea house that I would visit with my Grandmother. Not my kind of romantic I guess.
Staff was restrained and impatient.
I do not recommend Seerose to Vegans. Vegetarians may have a better time here.