Just read your reply above, and I'm thinking that magic being different than stories/expectations does have potential for building the warrior's fascination. Thinking along erotic lines, like, maybe he'd been told that magic was life-sapping (read: castrating/impotence-inducing --- this is something witches were often accused of in real life), but then the healing of the plant could be a good opportunity for suggestive (but horror-tinged) pseudo-erection imagery, the skeletal husk of the plant becoming firm and fleshy and suffused with vital juices and all that. Okay, that was a bit shameless, but I hope it helps.