Yup, that is the point of the retaining walls, they "retain" the soil. As it is, everything I plant, has a little semi-circle of rocks around the downhill side of it, to retain the soil around it.
I didn't terrace, that is make flat areas behind the retaining walls 1) it wasn't practical on such a steep slope-- I would have had to have at least twice as many or they would have had to be twice as tall, which you can't do with the interlocking blocks. 2) It wouldn't look natural and woodsy as a series of flat terraces.
But it does mean even with the retaining walls, I still have to work to help the plants hang on to soil around them.
And yes it has been a bunch of work getting all those blocks to where they were used, etc etc. Not so bad on level 1, but getting to be a big deal where I'm working now!
Thanks for the kind words everyone! Part of why I love this forum... Somewhere to show all that work where people understand and appreciate what went in to it.