I guess the oldest outdoor plant I have is a coralbells (heuchera) originally from my great grandmothers garden in Bluefield WV. The old home is long gone, its footprint is part of a parking lot, but before that happened my grandmother (lots of relatives lived in that house, as did we at one point) moved to another house and took some with her. I got some from her before she passed away, and have it in a container garden that will soon come to our new house (moving containerized plant collections is so much fun....and I can imagine how much more fun moving garden plants will be). My oldest house plant physically in my possession is a Cattleya forbesii I got back in the 80s I think, from a Brazilian orchid nursery as part of a collection. That was when obtaining plants from outside the US was relatively straightforward, unlike today. It has seen many former companions to the grave, but it persists as a tangled mass of roots and leaves, and in summer it sometimes makes it s ubtle but nice flowers. Another plant that has not been in my possession as long as the Cattleya, but is descended from a very old plant indeed, is a Christmas cactus I propagated from one my grandmother had. She told me that it came from her great grandmother (a propagation, not the original plant, that would have been tree sized I would think!). One of my sisters also grew a prop of it in NC but accidentally let it freeze on her terrace a couple of years ago. I still have one or two, they are very old fashioned with very small joints (all the commercial varieties available nowadays are much bigger plants with larger segments or joints) and simple pink flowers when it feels like flowering. It is neither as robust nor free flowering as the newer commercial kinds. Ernie DeMarie Briarcliff Manor, NY z6/7