I've had a goumi for 10 years and haven't seen any evidence of it spreading. I live in the bluegrass region of Kentucky so don't know if that affects propagation. It is wonderfully productive and has a delicious fruit that I mix with blackberries that come in just a little after the goumi to make jelly. It has a seed that can't be pitted easily but you can heat the berry to extract juice then use a food press to separate the pits.
