Another favorite part of gardening for me is seeing what comes back year after year. I've noticed that certain cultivated plants seem to reseed themselves better than the original sowing; in other words, I'll get a few plants from a single seed package, but then they'll propagate via seeds by many, many, many... Although, I'm not sure if it's because the subsequent generations are more vital or if the seed package had a bad batch
And some just don't propagate.
Couple of examples are Cosmos, Sunflowers, milkweed, Sugar Baby watermelons, morning glory...Although, I guess a major factor in all this is the amount of seeds produced vs. what you get in a package.
A surprising cultivated plant is broccoli (at least in my very limited experience) that propagated in a big way. I planted them for the first time last year from a seed package that a neighbor gave me, nothing special, just a plain package you may find in a Walmart. Only two plants survived from all those seeds, but one was a very hardy and large plant and produced many flowers that the bees went crazy over (the second plant wasn't that big, but it did produce some nice flowers.
And after the flowers went to seed, the birds went crazy over the seeds and I didn't attempt to save any. Then on top of that I dug around my yard a lot burying a lot of wood, so any seeds that were in the top layer of the soil were buried with the wood. However, this year I have well over a dozen broccoli plants that came back from those two plants and most of them are very big and beginning to produce broccoli heads. I wonder if I'll have enough bees to work them, along with all my Florida Betony and Spiderwort, which will flower about the same time.
BTW, right now the bees are loving the purple wood sorrel