Arid gardens are typified by sparse planting and blue-grey spiky plants. If you’re considering an arid garden then not surprisingly make sure you’ve good drainage (or build the ground up somewhat) and plenty of sunshine.
For planting you can’t go past the large blue-grey Jelly palm (Butia capitata) or the Mediterranean Fan palm (Chamaerops humilis) which comes in both a green and (incredibly slow growing) rarer blue form. Another palm with the perfect look for arid planting is the date palm (Phoenix dactylifera). Some forms are the most amazing blue-grey. Less common but worthy of note is the Palmetto palm; either the trunking Sabal palmetto or the dwarf Sabal minor.
Of course no arid planting would be complete without a mixture of Aloes, Agaves, Dracenas and Yuccas. Another plant worthy consideration is the Ponytail palm (Beaucarnea recurvata). These are often sold as tiny pot plants but ancient plants may reach two storeys high with truly massive bulbs at their base.
For colour try the Bird of Paradise (Strelitzia reginae) and some of the more unusual red hot pokers (Kniphofia). Not forgetting the fantastic displays of flowers on different species of Aloe.
Finally, as ground cover you can’t go far wrong with Mesembryanthemum.