From my youth that I don't see much since I left the coast...
Castor Bean - Nice plant of useful size. Some of them put on a beautiful display of fuzzy red and green seed pods. We all were taught early that the seeds were lethal if chewed. Maybe I'll see if I can grow another here. I once had a volunteer, but it didn't come back from a freeze.
Oleander - Another really nice tree/bush of a useful size. Nice flowers. They used to line our street. And many lived to be quite old. Also merited caution. Visitors sometimes came to grief when they cut branches and used than a skewers over a campfire.
My favorite of all is not rare but around here is certainly old-time, the live oak. I have three on the property, all old. The apparent oldest is next to the house and I believe is something like 250 years old. Far from the oldest in the area but worthy of being on the register. This one has always had a bee colony living in it. (And usually a snake in a hole under it. And once a great horned owl raising young in it.) Evergreen, simultaneously drops and replaces leaves periodically. Once upon a time, before wild horses and cattle dropped mesquite and other brush seeds all over, South Texas was a vast expanse of three-foot tall native grass with mottes of live oak scattered throughout.
