Approved plant list
It would be far easier to write a list of prohibited plants which would be much shorter. A list of invasive species would be sufficient.
It makes sense to use plants that are adapted to an arid climate instead of using imported water guzzling varieties.
In addition homeowners should be allowed to have annual wildflowers in their front yards. The Sonoran desert enjoys a stunning display of ephemerals only about once every five years or so. This fleeting display of natural beauty lasts for a couple of weeks and then is gone until the next time that winter rains provide the right conditions. The homeowners who have them remove the spent plants as soon as they are done blooming.