Morning or afternoon sun?
Coastal or inland?
Any specific color?

Zone 9 inland, any color except orang, yellow and reds, the area is under a very large city shade tree, with dapples of sun coming through and varying constantly. Thanks

The current name for these areas is 'hellstrips' --- google it and you'll see.

I have a filtered shade Geranium endressii, prob. 'Wargrave Pink', that I love. Competing with tree roots it may require more water than mine (heavy soil - once a month if I remember). Pink flowers. I like it better than 'Rozanne' (lav-blue).

Ajuga, Siberian campanula, dwarf plumbago, violets, Santa Barbara daisies. All require some water. Heucheras might do well and they require very little water.
Renee

In addition to Renee's excellent candidates, I would suggest some white gazanias and/or white or pale pink iceplant. These would do well in part shade rather than part sun, so I'd place them accordingly in the sunnier edges of your hell strip. I'd also buy them in bloom to make sure that the pale pink is indeed pale, and not that eye-maiming fuchsia that we refer to as poke-your-eye-out-pink. Other possibilities might include plants with striking foliage rather than striking flowers -- variegated abelia, or some helichrysum (lime or grey), or some ipomoea (lime or chocolate), perhaps. Both of the latter would weave themselves through your other plantings. I also like arctotis, which has lovely silver grey foliage in summer when it is not in bloom.

Kay

Thanks everyone!