I think it's a rounding error either way, but our pot for black tea only gets rinsed (usually cold), and our pot for herbal teas occasionally gets put inside the dishwasher. Not sure why you think teapots need to be washed individually.
I assume the environmental cost is dominated by other factors that apply in both cases: growing the plant, transporting the product, heating water to boiling temperatures.
I assume the environmental cost is dominated by other factors that apply in both cases: growing the plant, transporting the product, heating water to boiling temperatures.