Several years ago I took a bus field trip organized by the Arnold Arboretum to Fred and Marianne McGourty's garden, White Flower Farm, and a beautiful alpine garden (I can't remember the name) all in Connecticut. It was a wonderful and inspiring day. I bought a few plants from Fred McGourty including a beautiful Frances Williams hosta and a blue perennial geranium. I carried these large, heavy plants back on the bus, balancing them on my lap. We planted them in our garden where they did very well. When we moved, I was determined to take my Frances Williams hosta with us to our new home. At our new home, we replanted it in a small border on one side of our deck. It flourished there also.
After a few years, I noticed there were lots of small hostas under the deck. It's dark under the deck and has about two feet of gravel -- no dirt. (I lightened the two photos below so they could be seen more easily.) I crawled under the deck and discovered there were also astilbe and allium plants that had seeded themselves and made new plants under the deck. We had over thirty hostas and over a dozen astilbes and several alliums growing happily and even flowering in the darkness under the deck in the gravel.
We dug them up and replanted them in borders in our yard. The hostas went into the small patch of woods in the side front yard. They all thrived and did a good job in filling up an area with little sun and dirt that was mostly fill our builder had added to the area. Over the years, we have planted around fifty hostas, many astilbes, and alliums. We eventually put up a lattice backing for the border as a nicer background than the under-the-deck view. The lattice seems to have somewhat limited the propagation under the deck, but we are still getting seedlings there, as you can see in the two photos above. It seems odd to me that the plants that are elsewhere in the yard don't propagate like the ones next to the deck. There must be something about the darkness and gravel that they like.
The self-seeded hostas, shown replanted in our woods in the two photos above, are large beautiful plants like their mother plant. They don't come true from seed though; all are slightly different. Most are a solid blue-green, not the yellow and green bi-color of the named variety mother plant, Frances Williams.