I don't have a design background like many of the folks here do, but I have dealt with a problem similar to yours. I've planted Thuja Green Giant here and elsewhere, and per the name, they get big very fast. Unless your neighbors are on a hill overlooking your property, the thuja are way more than you need. I don't know how their roots would be when they are large, but I believe there would be a risk they would over time start to lift your wall. An inch would be more than enough to crack it. I imagine the frost line there is not very deep? How high a privacy screen do you need? If it's just 12-14 feet, there are many shrubs that would work, with essentially no risk to the foundations of any structures. Plain old forsythia would work. Or do you need an evergreen?

Ken, thank you very much for your comments! Here is some more info; if you can add to what you've already written, I'd appreciate it. The walls are made of 12-18" natural rocks dug into the ground just a little, with no foundation since the walls aren't very high. We hadn't thought about eventual large roots moving the rocks in the walls (we've been more concerned about the gophers destroying them!), but I'm sure you're right about this. The Tanyosho is behind a long wall that faces the house (west, but there are lots of oak trees that block the afternoon sun from the wall) and meanders across the front of our lot about 20-30 feet from the street. The land slopes gradually down from the street and then back up in front of the house. This wall was put in to hold about a foot of top soil that was added to the slope so I could plant shrub and floribunda roses out front to get the morning sun. If the roots push out the wall, that would still be ok since there is plenty of space below this wall, and if it becomes a rock garden instead of a continuous wall, that could also look very pretty. The wall doesn't have to be there to hold the soil (I didn't want to spend the money), but my husband just thought it would look nicer with a wall, and it does. We know about how large the Tanyosho gets in about 25 years since we saw a couple out at Hidden Lake Gardens where my husband fell in love with the exfoliating bark. They look just like the second one on the left side of the pictures in the link you have in your post (BTW, I love the bonsai!). Since we went out there after having you recommend HL Gardens here, you probably know which trees I'm referring to! The Emperor I and Waterfall are behind a southeast facing wall in front of the house that gets filtered shade for most of the morning. In the summer, they get the most sun early to mid-afternoon. There's room below this wall for more rocks and soil to be added and to have a rock garden if the wall gets moved and destabilized by roots. This is probably what we'd have to do, since the wall is very necessary since it is holding up a lot of fill that has the paver walk above it going from the driveway/garage area to the front porch. The Emperor I was just planted last summer. I had to water it and the Waterfall (planted with the Tanyosho 2 summers ago) constantly to keep their leaves from shriveling up. Our soil is loamy sand with a few inches of top soil added on top. We don't have anyplace else we could transplant them to since there's not enough sun elsewhere on the lot, so I was just trying to figure out if they all are likely to survive over the long run. I also remembered how clearly defined the root layer was when they dug for the foundation of the house--everything below about 6" was sand, with no roots or other organic matter. So I was trying to envision where the roots of these 3 trees would grow--down for a foot or two to get to the next layer of soil at the base of the walls where there would be moisture? I didn't know if they could live under these circumstances. I'm not as worried about the Tanyosho, since we were told to water it sparingly, if at all. Anne

Thanks for the compliments! In Cali you have to take advantage of every inch of space you have. If I planted zucchinis and cukes in the ground already, can I transplant them? If so, when? My zukes have sprouted their seed leaves, but not their true leaves. I want all my kitchen garden in this part of the yard, but I want something that will grow over the wall. What do you think of planting thyme and rosemary in the 3x1 boxes with a cucumber and squash this year, before the rosemary and thyme fill in? BTW, does anyone else have trouble logging in from Firefox? I can only login from this computer, my other one doesn't let me???

Olives are pretty fast growing trees. I planted some liners and some 5 gallon trees. In 5 years the liners had caught up to the 5 gallon size. They were all producing lots of fruit by then. The difference between the 24" and 36" will probably go away in two years time. Olive trees transplant very well. If you are not willing to wait you can have a full sized olive tree transplanted but you will pay a premium price for that. I'm not sure what you would pay in your area but in the Sacramento area in the early 2000's you would pay about $2,000. When we moved from the Sacramento area our neighbor took a few of my mature trees to his house next door. He had a front loader and dug them up and transported them and installed them. He said they had a somewhat lower production the first year but then they caught up the second year. Planting on your berm will help. Our area had nothing but clay so following the orchardist lead in our area I planted everything slightly high to help with drainage. Good Luck.