Answer: Agave attenuata, yuccas, flaxes (Phormium), aspidistra, grass-like liriopes, even a cycad are all striking in form and require little water. Other possiblilities:
dwarf bougainvillea, agave, yucca, Nandina domestica, gazania, amaranthus, annuals (petunia, lobelia, etc), geraniums in wall pots. You could even try citrus and some lettuces if you're willing to water more frequently.
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