Q: My neighbor planted Oelander on an easement close to street where lots of neighborhood children and elderly walk, in IN

A: All parts of the plant are highly poisonous. If you are positive of the plant's identity, your neighbor must be a moron. Nobody would want to assume the liability for causing serious illness or death to humans and pets, irrespective of their age. If it is their property, they have a right to use it as they see fit. I have not done research on poisons but if I had a client's family member was poisoned in this scenario, I would argue that planting highly poisonous shrubs constitutes an ultrahazardous activity. When one engages in an ultrahazardous activity, strict liability applies. Why does that matter? Under most circumstances, you can only be held liable for reasonably foreseeable consequences of your actions. However, when someone engages in an ultrahazardous activity, they are responsible for any consequence, irrespective of whether that consequence was foreseeable. That said, the state of California intentionally uses it for areas adjacent to roadways because it is so resilient. It is not cultivated in Indiana because it cannot survive prolonged exposure to frost much less the severe Indiana winters.

People very often ask whether they can "make" someone do something, as you have done. It is entirely possible that your neighbor has no idea how poisonous they are and is further unaware that they will not survive the winter as they are not inexpensive. They are available with free shipping from the Home Depot for $35 apiece. My best advice is that you complete talk to your neighbor as a first step. Do not be confrontational. Simply comment that you noticed their new shrubs and ask if they realized that the plant was highly toxic. If they are from California or recently traveled to a southern climate where they saw them they may have asked what it was because it is an attractive plant with attractive flowers and they would have been told that it is very resilient. If your neighbor did not realize that it was a highly toxic plant, they may voluntarily remove them. If they tell you that they know they are toxic, you may wish to do more research.