You have done a beautiful job of tucking plants into the crevices of your retaining walls. Your house trim color is perfect -- just slightly lighter in hue than the retaining wall blocks. First I would paint the big, flat gray wall slightly lighter than the blocks and slightly darker than the house trim. The concrete walk and stairs I would stain a mottled blend of the blocks and the house trim colors. Next would be to paint the railing black or the house body color. Now, think of the following as creating a light, airy trellise structure from the walk-level face of the (currently gray) wall to about 7' above the top of the wall (using 6x6" posts attached to the wall) with a corresponding line of posts sunk into the terrace level 2' in from the outside edge of the wall-attached posts. The inside posts would be about 6-8" higher than the outside posts. Put 4x4" wood to attach the outside line of posts to each other and do the same with the inside line of posts. Run wood pieces at the top of the two lines of posts from the inside line to the outside line at about a 45 degree angle. They would be cantilevered up at the terrace level. Across the top of the angled pieces create your top trellise boards which run parallel to the two lines of posts. OK. There you have your basic structure. You might want to extend the structure around to follow the street side of the terrace. You could then follow the suggestion of reom10 above about creating a bench-planter on the terrace side. Your spacing of the boards parallel to the gray wall and attached to the outside posts would determine how private you wanted your terrace to be. You might want to soften the terrace "floor" by using something irregular like flagstone with groundcover plantings between the stones. From the latticework on top of your structure you could hang seasonal flower baskets. Plant vines to go up the trellis and spill down the wall. How about planting a row of tall, narrow shrubs along the neighbor's fence above your terrace to help add to your privacy and make your yard feel less 'structured'? Or, how about patio table/s with umbrellas to block your neighbor's view? Anyway, you have a fun project ahead of you.

Ozbern: we had a similar dilemma, lovely backyard and then they started tearing down bungalows and building four story townhouses all around us. I built a single depth pergola along the back property line, the beauty of this is not only the privacy, but it brings the scale of the yard down to make it feel more intimate when we are outside. We also added a 10' x 10' (little over three meters) pergola right up against the house where we had a wall of windows. Will try to find that photo too. We have coral vine now growing in it. Dies in winter, comes back in spring. You can always do more contemporary details if this is too casual.

Sorry I am so late coming to your site - you are an inspiration to all, homeowners and advisers alike. For your planting advice, I suggest you call Merrifield Garden Center to see if they will come out your way. They currently have wonderful garden centers in Merrifield and Fairfax (both in Fairfax County) and a new one in Gainesville, but they may come further south to wherever you reside. (www.MerrifieldGardenCenter.com) Even if they don't send designers to your area, they are worth a trip to see their huge selection for a day of pleasure and inspiration, or to pick up some plants. Most of my clients are in the Fairfax and greater Washington area, but I am currently living out west below Front Royal, VA on the Shenandoah mountainside - wonderful views. cascio.offsite@gmail.com

For a pass through window to be very useful, it needs a surface to place items that are being passed through, that can be easily reached from both sides, or you would need to coordinate people inside and out to pass things, which isn't feasible. I would consider whether it will be used as a pass through, given the door is immediately beside it. A small breakfast bar that uses the window for a view can also be useful for a pass-through set-down surface. Make sure the window is large enough to give a line of sight from person to person so that it is easy to communicate between the spaces - along the lines of 'Could you grab another beer?' or, 'I forgot the sauce.' I would also make the pass-through window a little wider if you do have a seating area, so it looks big enough to be welcoming, or it will be less likely to be used. At 2.500 deep, the deck is not large enough for a comfortable outdoor dining area of more than a couple of people. You need 600mm for comfortable seating on each side of a table, plus the table width which will be 900-1200, and with this layout, you also need another 900 mm to allow access past this, to the pass through, the seating and to the steps down, and with the deck being above ground level, space for access beyond the seating on both sides of the table is a good idea. If there is a barrier, you can get away without it because chairs won't fall off the edge, but it does make things tight. That adds up to at least 3000-3500 and preferably more. You can make things work with a tighter space, with a compromise to fixed seating along the edge, and a narrow table.