I have built a horizontal fence on a slope. There is a 6" or so gap between the bottom of the fence and the ground on the downhill side. What easy solutions are there for this problem? I have considered: (1) putting some fence wire along the bottom, (2) trying to put in a angle-cut board, (3) putting up some decorative fixture (e.g., small garden edging fence). I'm looking for the easiest solution given what's already done.
I don't know what your goal is, but if it's merely aesthetic (and not for pet or child containment), I'd be inclined to cut a board diagonally. Mark one end at a height equal to the difference in the tops of the two adjacent sections (which looks like about 4 inches). Mark the same at the other end, but from the opposite side. Cut a straight line between marks. This leaves you two nearly-triangular boards.
Install one piece at the bottom of the first section, and the other at the top of the second section. You may need to use additional screws vertically at the narrow end, fastening the last board to the one next to it.
Now you have a nice visual transition without any abrupt jobs. The fence follows the landscape instead of fighting against it, but it retains the nice horizontal orientation in the boards. Adjust grade slightly to account for any remaining gap at the bottom, or add a little additional mulch.
Just put another row(s) of boards in. You can scribe & rip the boards to follow the ground, keeping them off the ground by 1/4". Or, you can dig out the ground for full height boards, take the dirt from the left & put it on the right for a foot on both sides of the fence.
Assuming the boards can't be bent enough to slip them in the channels. Cut the boards in half or wherever you find most appealing & least obvious. Half-lapping the cut zone would be best, but you can also just screw the boards back together with a board scrap.
Really Nice job by the way. I'd prefer to keep that color contrast as long as possible. I'm on a One Time Wood Protector kick, if both sides or just your side gets a few hours of Sun a day it's the only way to go. If the fence is wet in the picture One Time's Natural will keep that. Not a promo, I just find that no-one knows about the stuff & they just keep ruining their lives with poly's.