How's day to day life in horticulture jobs? How labor intensive is it?

I am about to start my first summer semester at my technical school's horticulture program, my first semester will be free which I am super stoked about. I am looking to get my AAS in hort. I live in the Carolina's where there are some beautiful public gardens around and the goal is to work in a public garden/estate or conservatory/greenhouse. I come from restaurant work so I am very used to being on my feet all day and I have no problem getting dirty and being on my feet in general. However I see horticulture get lumped into landscaping a lot and I don't have it in me to do that kind of physical labor, I have a bad back and I want something that won't kill my body long term. So those who work in nurseries and such, how is the physical part?