We forgot that we bought one of these a few years back and just assumed it was totally wild. Looking back at our records we did plant one whip back in 2022 and it's no longer where we put it...so maybe it survived long enough to end up in some animals who then distributed them around the yard.
The pictured grouping is off the back deck.
About 20 m and unlikely - we have a section with a bunch of different compound berries including a few types of raspberries and loganberries where it was planted. We are constantly fighting the spread from those patches, but they pop up fairly close. There are none in between the planted area and this one.
Some other varieties have popped up in other areas. We have another kind coming up about 10 m from these ones (forming a triangle with the original patch) and some on the driveway eminating from the garbage storage area (where the chipmunks have a nest) and also just in the front of the house interspersed with the loosestrife.