I am still eating food from plants that were started by my great-great-great grandmother...
When our canals were dug 150 years ago, the workers made a point of burying their
apple cores along the banks. Many of them sprouted, survived, and are still providing fruit today. Asparagus likes growing along ditchbanks, and since that ground was unsuitable for planting crops due to being so uneven, asparagus was planted along the ditches. We no longer use the ditches having converted to a pressurized
irrigation system 40 years ago, but the asparagus is still feeding my family each spring.
I collect mullein from the wildlands. No telling how long it's been growing there, hundreds of years I suppose. That was introduced from Europe.
I grow corn... That came up from Mexico around ten thousand years ago. I'm still reaping the benefits. I've tried many times to grow corns from Oaxaca, alas, they fail in my garden. But for generations they failed, and failed, and traveled a little further north from time to time until they finally became well
enough adapted to grow at my place. The plant breeders continued pushing the boundaries, and today corn grows as far north as Alaska.
I still grow onions that my aunt's mother-in-law collected from my great-grandfather's farm. That's as far back as anyone's memory reaches. No telling when they were originally planted.
There is a grove of apricot
trees growing where my daddy used to have his clubhouse when he was a lad. They'd pick apricots from the orchard, and climb the hill to the clubhouse, and eat the apricots, or throw them at each other. One of the pits germinated and survived, and has created a grove of apricots 65 years later.