The problem comes in when you try to farm them as the plant's leaves only gain this property if it's grown in an environment rich with life magic like a large forest or deep in mountain ranges. While you can grow the plant if there isn't enough life magic it won't gain its magical effects rendering it into just a red bush. But if you have a life affinity like I do and get your hoofs on one you basically have an unlimited supply. With this in mind I've already filled the other pots I bought with more of the tea plant and after learning how to make tea I started to produce blood leaf tea.