and I have so few that I have bought surviving, that I refuse to buy perennials anymore.
My trip around my garden in my head: Peonies from my grandmother planted in the 60's in a place that would never be suggested if I had researched it. Pachysandra everywhere from a neighbor. Ginger saved from a wild area that was being excavated. Goldenrod, dame's rocket, and sweet peas from the roadside. Cranesbill taking over in several locations. Bishop's weed that someone should be slapped for passing on to anyone, as well as mint and honeysuckle. Lizard tail given to me for an area where nothing would grow---it did too well.
My favorite is purple lamium that somehow rooted on my brick patio where fall leaves had built up. I have left it and the whole patio is a carpet of lamium now. Why I love this is because I tried to get the bricks out so I could put a garden in there...impossible, but I still got the garden there.
What have I learned from this? Never accept plants from anyone who is getting rid of "surplus", because that means that it is a lot of work to keep in check---and I don't do a lot of work well.