Your neighbours don't seem that fond of plants in general, i guesse! I would make sure, in a mild fashion, they don't repete that kind of behavour. I can imagine how you feel about it! It' your precious, and they just treat your surroundings like ****, just carelessly polluting.
I never use those weedkillers at all. But, ofcourse, it's a big industry.
Easy to garden your way into a moonlandscape! There are many alternitive ways to kill particular plants in the garden....
I think if it's been a weedkiller based on chemicals the rootstock can still be ok, but if it was based on hormones everything will die off, even the rootstock. It's created for that kind of plants with rhizomes. The cells bearst open and the whole plant dies.
Anyway, i wish you all the best.
Greetings,
Gunther, Brussels