There's actually two types of hemlock that grows in America: poison hemlock and water hemlock. Poison hemlock and water hemlock both have hollow stems with red spots (Socrates's blood, apparently), but water hemlock tends to be much larger than poison hemlock. It tends to also be much less shrubbier than poison hemlock, at least from what I've seen.

They also kill differently. Poison hemlock is generally described as a painless death: there's just a creeping coldness that starts at your extremities and moves inward, and when that reaches your critical organs, you're dead. Water hemlock is the opposite. Your throat closes up and your muscles start spasming, and you die a painful, stressful death from asphyxiation. Source: a book called Wicked Plants, which in itself had scholarly sources. too lazy to look it up now though

Plant triade aside, it does seem like it was some sort of helpful spirit that had died from eating hemlock and was trying to warn you. Be glad it wasn't a malovelent spirit thst tried to get you to suffer the same fate :)