20 of the World's Deadliest Plants

Nerium oleander (aka Oleander)
This shrub is one of the most dangerous on the list, which is bizarre on account of how widely it's used as a decorative shrub. This bush pops up in parks, schools, and back yards all over the country, especially in the southern and western regions of the US. And while it might be nice to look at, don't go chewing on any part of it — its leaves, flowers, and fruit all contain chemicals known as as cardiac glycosides, which, while therapeutic in precise doses, can put you into cardiac arrest if ingested unsystematically.