My front yard connects with a neighbors what can I use to seperate the

Brenda, about the only chance you have of avoiding your neighbor’s weeds is to keep an immaculate yard yourself so weeds do grow up to seed, and to create some kind of barrier between your yards, if possible. The wind is going to blow weed seeds into your yard, even from far away. But you can try to prevent the weeds with runners by keeping the space between your yards not weed-friendly. If you are allowed to plant shrubs at the property line, do so! A concrete block fence would work even better, or any kind of solid fence, even two feet tall. In my neighborhood, we are not allowed to have fences in the front yard, but some people have planted shrubs with no city interference. But, to tell the truth, the people who really work on their yards, or who hire a lawn service, have yards that are distinctly different from those yards whose owners only cut the grass or weeds when they are threatened by a citation! But most people take care of their yards. I looked for a photo of the yards across the street from ours, but apparently the only pictures I have taken is when we have had snow, and that’s not often in Mesquite, Texas. I do wish you well ☺️

bushes! shrubs! Azaleas at least bloom and look GOOD

you could put up trellis's for vining flowers like morning glories. moon flowers or Ivy. you could make them with a few posts and strong line as the Panel/trellis. I too have a neighbor that has an unkept yard and this is my plan to block their yard from my sight....lol

if you cant put up a fence ( I assume not even one that slopes down gradually) I would plant some nice, thick shrubs to divide the area, and perhaps a ground level concrete border on the neighbors side of shrub. I don't know if there is anything that will keep weeds from growing in your yard.