Those look like blue Tequila Agaves. The tree? Palo Verde? I'm really guessing big time on that one.

Trees could be mesquite of some sort. Definitely a nice look for arid climates.

Yeah they look like Agave tequiliana. The tree might be Chilopsis. The leaves look a little too big to be either Parkinsonia or Prosopsis. The pics are not really good enough to make any sort of accurate ID for either though.

I cannot even make out the foliage on the tree, but it does appear to me to have zigzag stems. Maybe one of the zigzag wattles, such as Acacia macradenia? They are occasionally grown in SoCal. A. merinthophora, zigzags too, but the leaves in the photo appear too lush for that one.

I looked up pictures of Mesquite and it does look very similar! Here I have updated some new photos of the tree on a closer look. It may not be as close as desired but this was the closest I could get to since the tree was located in a neighbor's yard.

can anyone confirm that it is a mesquite?