This year (granted this year is odd on many gardening levels) I've been surprised by many a plant thought long gone only to have it pop up and put on a show.
I buy cheap gladiolas bulbs because I'm typically so sick of gardening by early November there is no way I'll get out there in the semi slush of cold weather and dig them up. I figure they rot and become a compost of sorts (rationalization is ever a friend of the lazy gardener.)
Violas and cleomes have self seeded in every little crack among the stones and bricks of the back walks. The cleomes even self seeded in an old wash pot I'd forgotten to empty of soil last year. Both have tiny seeds that manage to lodge in minute cracks and push a piece of cement aside as if it was nothing.
I have sunflowers blooming where the grass has gone dormant. Tough little beauties.
The year we had to replace our north basement wall, all the soil was back-hoed out, piled high and then refilled in construction guy manner. Top soil was mixed with soil that had laid in place since the house was built over a hundred years ago. Nothing should have survived. While we let the ground settle for the rest of the year, to our surprise up pops an array of cannas. How did they survive? How did they manage to be replanted near enough to the top to make it push through? How fun!
Morning Glories and a lone little sweet potato vine have emerged to brighten the summer.
Have you ever had the accidental success of a repeat? I'm sure it was all the peace and love!