Since the walls are concrete, I assume you are in a mild climate where deep footers are not needed. And the top of the retaining wall at the rear of your property is higher than the top of the sloped wall at the NE property corner, If you look up the sloped wall from the NE corner, at the top the soil grade falls against the wall. down the slope the soil grade is near the top of the wall, At the NE property corner the yard grade is somewhat higher than the top of the sloped wall. The above being shown in profile on the left side of the graphic below. I suggest you build another short concrete wall about a foot inside the sloped wall as shown above. Dogleg the end at the rear wall to allow a place for yard water to flow to the corner. The area between the walls should be concrete to carry any water flows without erosion. If the maximum height of the new wall is 16 inches, it's a reasonable DIY project.

Good idea! I know they can kill trees if you smother the roots. And so can hacking through the roots to put in a bed! I'm hoping I can get the right depth so I do no root-hacking AND no smothering. Fortunately, my fondness for shrubs means that once I have everything planted, I won't be doing huge amounts of messing about in the bed and can leave the tree roots alone as they come through again. We're going to add on to the front of the house--the left bay will come out about 30' more than it is now. I'm going to use that to take a wall straight across from there and up from the corner of the (currently) red section to create a courtyard. It won't have a gate--the doorway will be open to the yard. Inside, I want a courtyard garden. A bluestone-set-in-gravel path will stretch from the driveway across the yard portion and to the courtyard. (Taking it from the street would look silly in this case.) There will be an open yard section there as large as most front yards. *g* Preferably, I'd love to do a no-mow yard in which I can plant some species tulips, crocuses, grape hyacinths, lilies of the valley, and the like in semi-artificial patterns among the grasses...not sure exactly how yet...could be kind of cool. That part of the yard would be ringed by a mixed shrub border to screen it from the neighbors and the front part of the yard, closer to the street, which will start at the first trees on either side. The front section will be pure entertainment rooms, divided by walls of beds. I'm going to have a full-fledged outdoor kitchen, with 3-5 other very spacious rooms flowing one to the next. The sorts of spaces are normally put in backyards, but with the kind of lot we have, they'll actually work better for entertainment in the front, and it'll look good there, too. I want a firepit and some sort of pond/fountain--I'm actually thinking of an above-ground, square and blatantly artificial pond that overflows into a rigidly geometric channel/brook. I am REALLY agaonizing over balancing the Asian and the modern-formal influences. Asian gardens are typically an abstraction or refinement of nature, and formal gardens are as artificial as you can get. If I get the balance wrong, it'll just look WEIRD. If I get it right, it will be fantastic. One thing that I'm thinking hard about is bed-shapes. Should I go flow-y or geometric? I could go geometric and have sort of a cascade of rectangles, which would be build of cinderblock and could either be plastered over or (another decision!) faced with bluestone. The bluestone would be more subtle, and I'm thinking it would soften the modernism while keeping to the clean lines, and it would look better with less rigid plantings inside... If I were in the UK, I'd have no problem finding a designer who often dows things of that sort. Similar styles are VERY popular there. Here, though, I haven't found anyone locally who has that kind of aesthetic or has demonstrated the ability to think along those lines. The house was designed by a European, so I shouldn't be surprised that I'm being attracted to modern European garden design to harmonize with it! Weirdly enough, it would be easier to merge cottage and modern formal than Asian and modern formal! *g* I have an acre of woodlands that will eventually become a more "pure" Japanese garden, though. I need to pull the plat. We're taking possession in the fall, so I'll have all winter to prepare the beds before planting in the spring!

Greenlydia, you can work with round rocks if you stack the second layer in further than the first, and to the extent that the rocks lean, make sure they lean into the side of the bed. In effect you are not stacking the rocks on each other, but rather embedding them into the side of the bed. I personally hate the idea of glueing and mortaring rocks together as I am prone to changing my mind about things, and the rocks can always be used for a different application if they are merely propped in place, but if they have mortar all over them they are hard to dismantle, and hard to reuse. Quite aside from which, the mortar doesn't actually make the thing any stronger. It just provides a false sense of security so that most people who use it are less careful about placing rocks so that their weight holds them in place. Both types of retaining can fail, of course, but if an unmortared rock rolls out of place... well, you roll it back, or maybe you repack the section where it came from. If a mortared rock breaks out of place, well, there goes the weekend fixing that. Regarding water, my own strategy with beds surrounded by rock retaining walls is to keep the soil level in them flat, not mounded, because I don't want water running down between/inside the rocks taking away the soil that supports them. I want the water soaking in where it lands.

Sheri, you don't have to actually raise the beds with an edging. You can just mound it up. Of course, this doesn't work well in an area where there will still be grass. I have about nine raised beds, but they are within an area that gets mulched. I'm using straw for the mulch this year, then in fall, I will rake it up onto the beds. Next year I'll go with either more straw, or woodchips, free from a landscape company. (Probably the straw. I get bales from a place that uses them for a children's play area, where the bales sit outside for a month, making them unusable for bedding, but still OK for my garden. They are free for the hauling.) I also use a 'sheet compost,' or 'lasagna' bed method. For more information on that, come on over to the soil,compost and mulch forum, and read the FAQs. Lots of good info there. Best of luck on your new garden.