We installed a flower bed next to our house. The house siding is T1-11. We put weatherproof paper against the house to keep the siding safe from moist dirt, but we would like to put some kind of trim or flashing on it for further protection and decoration. Does anyone have recommendations for this trim/flashing?
I'm assuming that the flower bed faces south. To use the bed with in-ground plants, you would have to build a wall inside it, so that that house-side of the wall is 6" from the siding (for airflow & weeding). This would be a large pain in the butt. I don't know the dimensions, but the bed seems large enough for one or two large containers. If it's 4 ft x 2 ft at the narrowest, you might be able to find something at a farmer supply store (make sure that you punch many holes in the bottom for drainage). But - you must still leave several inches between the side of the container and the siding. A collection of largish pots may also work, but would require more watering.
The idea behind the containers is that their height is no greater than the height of the flower bed's walls (a little lower is better), so that when you're looking at the house from the side you don't see their tops. If using a single large container, add mulch to it to help hide the container's sides and hold moisture; if using two or more containers, a small-sized organic mulch would be nice, then cover the spaces between the containers (and even on top of them to a small extent) with coir (ground coconut husks), sphagnum moss, or sheet moss. You can get coir in sheets or shredded; you can possibly find moss at a florist shop or online.
Another option may be a plastic liner for a pond (https://www.homedepot.com/p/Algreen-Avonlea-33-Gal-Rigid-Preformed-Pond-Liner-91901/206704125) - again, you must punch a lot of holes in it for drainage. Finding one to match the flower bed's shape would be a challenge, however.
I have ponds so I always have some bits of pond liner or EPDM around. This is waterproof, resistant to UV and quite tough. You can cut it to fit with a pair of scissors or knife and it can be glued in place with silicon or latex caulking.
Really, a thousand and one uses, including soil barriers for invasive roots, flaps that go over locks and prevent rust....