Hayward's cacti Hillside...
A few blocks down the road are these Opuntia ficus -indica growing in a precarious position. Others are more secure below. Toss in some other non natives like Syzgium paniculatum and Pampas grasses. Those cacti might be in even greater number except they are growing on a Latino church's property and no doubt the pads are harvested to some degree every year.
A few miles away another type of ecological takeover by blue Agaves for another time...