It depends a bit which weeds, and what their method of spread is. In almost any case, the black plastic edging will probably be a waste of time. Weeds that spread by runners, like daylilies or morning glory, will easily bypass even quite deep edging, and most weeds spread by seed so will come through the fence. As such, if you add some boards to the fence from the ground up you might make the most impact, but even that will be bypassed by seeds to some degree. But for seed-sown weeds, to some extent you can depend on the shade your plants are going to supply to limit the degree to which weed seeds find hospitable ground on your side of the fence. The better your shrubs cover, the less weed growth you will have... "the trick is to cover the ground," as a nursery near me once wrote in their catalogue. As your plants grow in, their root competition will also help to reduce weeds. The real key to ongoing success against weeds is to design into your border the capacity for you to get into that area and pull weeds early, and probably also to put down an annual covering of mulch. Either open areas or stepping stones, in other words, which will not show much among your plants in summer, and can maybe add a nice structural/pattern design element in winter. What you can also do is plant a groundcover that you like that will grow over toward your neighbour and maybe suppress his/her weeds a bit, or a lot. In my climate something like Asarum canadense would do the trick. But you have to want it in your border too! Ongoing vigilance and access, and discreet use of herbicide on weeds that grow by runners, is the nutshell answer that I would offer. That, at least, is how I approach my neighbour's weeds, which include morning glory and buttercups, and so attack via underground runners, surface runners, and seed through a spaced-board privacy fence. Karin L

I've trained a trumpet vine along a similar fence, and had considered doing the same with wisteria. The primary downside is getting to your neighbor's side of the fence to trim and train :-)

Some 25 years ago I erected a three rail split rail fence with wire screening - my back yard, About three hundred feet, three gates, all by hand and I was the only worker. I dug each post hole with Fence Post Hole Shovel. I painted red rings around each handle so I knew how deep to dig and I did not have to use a tape measure for depth. The depth was that which I needed for the post plus about 4 more inches. This was to accommodate a flat stone that I lay in the bottom of the hole to set the post on. I mixed concrete and shoveled it in for maybe ten - twelve inches and filled the rest with soil and any rocks that I had. Plumbed the post and supported with lumber. Went on to the next hole and repeated. Would do this for a half dozen or so posts, and then drink beer and wait for the concrete to set up over night. Next day, erect the rails between posts and then dig as before for more posts. It worked fine and the neighbors agreed I had earned all the beer I drank. 25 years later I'm seeing more and more of the posts rotting out, typically at ground level. If this helps, I've got some more tips for you. However, I'm sure there are some folks here with much more experience than I have!

Cedar rail fences are a big nostalgia thing for me - but the ones I remember were Grandpa’s snake rail fences that ran between old spruce trees (which provided the vertical posts - and spruce gum for us kids!) I don’t particularly remember lichen but there was lots of wild blueberries and bunchberries growing along the base of the fences - along with moss and starflowers…. The trees were quite old when I was a kid and they had an unfortunate tendecy to come down across the road in a winter storm! I remember people pounding on the door in early morning after a winter storm took down a tree - the people needed our help to clear the tree off the road so they could get to town to go to work. Aahh the early 1960s in rural east coast in Canada…. ! Lichen there was - but it was insignificant in the overall picture - and we didn’t know (or care ) what the names of specific varieties of it were :-)