Toxic honey

I have heard about honey made from rhododendrons. Are there any other plants of which one should be aware and not have growing in their bee yard?

You are referring to "Mad Honey" which, per the article in the link, only comes from bees that visit certain types of rhododendrons.
Specifically in Turkey, this honey is made ON PURPOSE because of it's druggy effects.


http://modernfarmer.com/2014/09/strange-history-hallucinogenic-mad-honey/

Another thread about the "mad honey" article: https://permies.com/t/39363/bees/Hallucinogenic-Mad-Honey-Turkish-Rhododendrons

According to the article, the "mad honey" happens where rhododendrons "grow in monocrop-like swaths". I would imagine that there must be other flowers bees like that could create problematic honey, but unless they become the predominant food of a particular hive, it's unlikely to be discovered.

You shouldn't be worried about having rhododendrons in your backyards. It's interesting article

https://mad-honey.com/blogs/honey-hunting-in-nepal/mad-honey-from-himalayas-nepal