Unless you have an HOA with plant restrictions, then it's none of their business what type of "native" plants you want to grow on your property.

My Neighbors use Knotweed on their propery for the same reason (seasonal privacy)- I don't think they know it's an invasive, but I just kill it if it goes on my property. What's on their property is their business.

VERY good point isabella__ma. Thank you!

Add more bushes and perennial native plants and yank up the "weeds".

If you add a thick layer of shredded tree branches you can stifle the new weeds for a while. Call a local tree removal company and you might get the stuff for free.

For good plant growth you still have to maintain a mulch anywhere you have otherwise exposed soil. For successful use of ground covering plants you have to choose ones tall and vigorous enough to keep down weeds once established, mulch and weed the planting before this point.

And in this area kinds like red alders and blackberries are still going to get into even a pretty tall cover like well-developed salal here and there, indefinitely.

And anything that creeps or spreads sideways is not going to stop growing when it reaches the property line.

The usual threads are the posted by the tidy folks who want to block out the neighbor's mess; not by the ones who want to keep their yards in a more unsightly state.

In abutting properties with "semi-mulched" strips, the one who doesn't maintain is always going to have their stuff encroaching on the one who does. Ground covers are nice, but without maintenance you've got weeds plus ground cover migrating to the neighbor - and they can deal with it as they see fit on their property.

Are the privacy plants you've got in your 6' wide space eventually going to grow over, block the neighbor's sun, etc.? Will you be upset if he prunes anything hanging over the 6' mark? Will we be discussing law suits if he accidntally gets too carried away with herbicides on his side that by chance migrated to yours?

Call me cranky, but I'd clean it up and invest in more mulch.

One low growing groundcover I've had good luck with is Veronica Georgia Blue. It isn't super cheap, but it will choke out weeds & create a fairly attractive carpet 3 seasons of the year. I got it at Classy Groundcovers. It is low, though, so it won't give you any more privacy.

I think getting the el-cheapo wood chips from a local tree place is probably the easiest thing to do. You can put them really deep (6-8") and that will smother everything for a couple years at a time.

Wow, thanks for all the feedback everyone! I like the idea of growing taller native perennials in the area as first suggested by lazygardens. And, cool thought about the blackberries! I was thinking about this last night and decided that it would be best to keep it at least a bit tidy, as we will have less of a mess to clean up if we ever resale.

I don't find you too cranky duluthinbloomz4. To answer your questions in light of what I said above: Their house is too far away to ever block anything like the sun. I think I'll invest/move some perennials around that I will not care about if they get harmed. I'm not trying to create an unsightly mess. This part of our yard is pretty far from the house and away from the street. I am just tired of my neighbors really. They have thrown stuff at me, yelled and us, and have thrown their cuttings on our property. I would report them to the HOA, but these things are always ammunition for the future if need be... I walk softly and carry a big stick.

I also had the thought last night of putting in some clumps of ornamental grasses! They certainly shoot up pretty fast in the summer. I would only have to get rid of the waste each spring. The Veronica Georgia Blue looks like a nice groundcover. Thanks.

Here in the Seattle area a ground cover planting needs to be at least 2' tall to have much of a suppressing effect on weeds.

Or the kind of effect most probably have in mind when planting ground cover for reduced maintenance.

And this will only happen if the ground is cleared of weeds before the new planting goes in.

Shorter carpeting plants can work pretty well if clean ground is used for planting and the site is very favorable to the kind of plant used for ground cover.

Kinnikinick on a hot sandy bank for instance.