I just bought a little piece of property and one of my neighbors has a lot of blackberries. They're almost covering their place so the blackberries are invading my place, along the property line. I was wondering if there was something that I could plant after I pull out all the starts in that area that would be tough enough to block them out. I know it a long shot but any suggestions would be helpful

Blackberries are tough.... And aggressive.

About the only thing that's gonna slow them down.... Is shade.
So...
Think a grove of trees, or a bamboo patch...
Even after shading them out.... You're still gonna have the dead sticker briars.

How much property do you have?
Isn't there some way to just live with them?
Blackberry fruit is good...

Yeah I can live with them. I just thought if there was something I could do that I would. I have about half an acre and the area that I'm worried about is like a 4 ft strip between my shed and the fence that runs down the property line. Its probably an impossible area to maintain. That's why I was hoping I could just plug it up with something less invasive.

One possibility is to dig a trench and install an underground barrier (partially above ground) to stop the roots from moving onto your property, once you've cleared the area.

It would be similar to a barrier to stop bamboo from spreading. I haven't done it myself but I know they do it in California where the bamboo spreads like crazy.

By do I know blackberries can overgrown and become gnarly. We have a really old row of bushes that will be cut way back this year. The key is to be able to get close enough to get to the middle of the plant without getting stuck in the prickers!

My neighbor's blackberries have grown about 10' onto my property. Now I tend to them and harvest whatever I want. You can train them to behave and reap the reward, if you like blackberries.