The nice thing about mathematics is that there probably won't be any failed or non-reproducible experiments in the lab. That doesn't mean that a math PhD is going to be easy, but you should be aware that a lot of people will have a different idea of what you are doing if you don't tell them that your PhD is in math.

Best of luck for your PhD! You might want to check out this ted talk: https://www.ted.com/talks/uri_alon_why_science_demands_a_lea...