Yes, there do seem to be some long-standing disadvantages to toting roots around--according to GURPS, Herons only carried roots when fighting at some distance from the city. I suppose that when they were nearby, more specialized healing wizards were close enough that the Herons themselves didn't have to do any medical work.
Herons learn a variety of spells as they age, almost all medical-related--healing, lending strength, sterilizing food and drink, slowing aging, and curing disease are just some of these. Half of their usefulness is due to how much they strengthen the lesser warriors they fight alongside, I imagine.
--SiliconDream
