They are aggressive through birds pooping them throughout the countryside. Also depends on the type of climate they are in whether that works good or not. I have some feral seedlings that have popped up in recent years, probably from all the plantings the government was promoting, but the
deer and
rabbits have kept them knocked down. I also have the cultivars and protect those, so they survive, yet they have had dieback from winter or cankers maybe too.
Remember some of the invasives are hyped and people make it sound like the sky is falling. Maybe in some perfect locations it is like that, but a lot of places have not ideal situations.