Check out the reviews of "Sedum Acre Gold Moss" at the Dave's Garden website. You would only need a few clumps to start. It will grow extremely fast & fill the areas you are describing. I don't believe it will be invasive as it will be contained by curbing on one side & sidewalks on the other. I grew some in southeast CT, zone 6 at the street end of a long flower bed and it was very hardy, but not invasive. The sedum was one of the few plants that would tolerate the road salt & sand every winter. It's very pretty when in bloom.

Gosh, the list for potential candidates is huge!! Are you looking for perennials or shrubs? As mentioned, a good many native plants are very drought tolerant, but there are scads of more ornamental exotics that exhibit similar drought tolerance once established as well. "Drought tolerance" is usually defined as a plant that will survive/thrive in correct soils and light conditions with little to no supplemental watering after it has become established. That is an important consideration - drought tolerance is not immediate, even for very xeric species. Generally at least one full growing season after planting with regular deep irrigation is required, sometimes longer, depending on the species. Personally, I lean more to the woody material when considering an Asian inspired garden - more of an emphasis on foliage and form rather than flower color. The nandina is an excellent choice. You could also consider barberries, shrub dogwoods, escallonia, hebes, elaeagnus, euonymus, Ilex species, osmanthus, myrica, pyracantha, spiraeas, selected vaccinium and viburnums. For conifers, junipers, yews and pines. For perennials, lady's mantle, hellebores, epimediums, armeria, helianthemums, euphorbias, bergenia, candytuft, west coast native iris and their hybrids and hostas (yes, hostas are very DT once established and some are very sun tolerant as well, especially PNW sun conditions). For grasses or grass-like plants, liriope, fescues, certain carex, pampas grass, miscanthus, panicum and some bamboo species all fit the low water requirements. Many spring bulbs will also work well - they appreciate our cool, damp winters and would prefer to be drier in summer - pretty much our typical natural rainfall pattern. For a bit more broader approach, most plants with mediterranean origins tend to be quite drought tolerant, as that's their natural climate conditions as well - cool, damp winters and dry summers. Some may be a bit incongruous with an Asian style garden, but not necessarily and certainly not all. And you can always check the Sunset Western Garden book's listing of plants for dry places for additional suggestions. Also, many of the better garden centers will have info sheets or handouts listing drought tolerant species.

I'd start with laurels -- Japanese laurel (Aucuba japonica...likely marginally hardy for you) or English/cherry laurel, Prunus laurocerasus. Growth with these is generally fairly rapid, but will be slower in drier conditions, so irrigation to help establishment is suggested. Yews are also extremely shade and drought tolerant but with a relatively slow growth rate.

I spoke with Keith Moore from West Feeds - he said if you are going to GPS the store use 7730 Dove Drive instead of 13758 Hwy 181 South. Guess CPS assigned the wrong address so you won't get to the right place.