I was going through old photos this evening, and ran across this one taken in 1975, a few months after the landscaping was installed at a new house I had purchased. The photo had faded to an odd color as photos of that era seem to do, but what struck me was how passé all the plants are today--at least here in Arizona. Not only the old-school plants, but the other elements like the railroad tie border, rooftop air conditioner, unnaturally colored granite, as well as the red lava rock used as mulch.
The plants no longer used much in desert landscaping that are shown in this photo are unsterilized Olive trees (considered an allergen), Oriental arborvitae (fine when young, but really ugly as they aged), Tam Juniper (woody and sparse as they aged), Pyracantha coccinea or Fire Thorn (high maintenance), Morning Glory (declared invasive and banned), Mulberry tree (another allergen and messy), California Pepper tree (incredibly messy) and some of the Eucalyptus trees (messy and subject to limb breakage). There are many more, but I listed these because all but two of these plants appear in this photo. The Mulberry and California Pepper tree were in the back yard.
Another reason all of these plants fell out of favor is that they all take moderate to heavy water, and over the years, homeowners who had desert landscaping in the front yards preferred more zeric plants. (Many folks still like to have a lawn and more tropical plants in the back). Very few people planted cacti in those days, but now, it's common, along with native trees and plants. The current trend is to place and use plants are they would appear in the desert. Another change is to use plants that are from Australia. Many do very well here and are low water use.
For those of you who are old enough to remember back several decades, are there any plants in your region that fell out of favor? Any landscape elements? What's new and different now? I'd be interested in hearing about them.