I know only a little about plants, so when I saw the one she was talking about, the shiny, waxy-looking leaves said "poisonous" to me. Which is probably what they were aiming for. But I totally get what you mean about it taking you out of the story. I was just reading a similar incredibly pedantic :) discussion on Ravelry about the knitwear on the show. It's all lovely but highly anachronistic. I'm sure to most people it evokes a feeling of old-fashioned and/or rustic, but if you know much about knitting or historical costumes it's a jolt to see chunky cowls, etc. on an 18th-century character. I think the show sometimes chooses to evoke a certain mood rather than be completely accurate, and that's fine except when it's within your area of expertise and is a distraction instead of an enhancement.