Our yard is nothing but clay soil and rocks and it's sloped. So when it rains, what doesn't wash away turns into a muddy mess. I would like to add plants on the biggest slope to stop the erosion. There are ruts where the soil has washed away, the largest is at least a foot wide and a foot deep. I've been googling trying to find the best way to stop erosion and everything says to rototill it and add organic matter/compost. That's great for level land, but I'm afraid that if I do that on a slope, all that hard work will wash away before any plants get well established. I've thought about putting up a retaining wall, but the bottom of the slope is on the neighbor's property which is up for sale and has been vacant for 2 years, so I don't know who to talk to to get the ok to build it.
Is it possible that I can just plant directly in the clay without amending the soil?
If I do rototill and amend it, what can I do to keep it from washing away while the plants become established?
Are there any other alternatives that I can try?