Fallbrook is known as the avocado capital of the world, the weather is apparently just right for them here. Like apples most commercial avocados come from grafts of an original tree rather than seeds, the most famous avocado type is probably Hess which all come from a tree discovered in a San Diego park. Another oddity about them is that the trees only bear fruit every other year, the one in my orchard has exactly one avocado on it, I'm hoping this is the off year!
A typical avocado grove near Fallbrook taken from US395 just south of Lilac Rd. Most orchards are on steep hillsides, presumably that lets the cold air roll off them. Must make harvesting quite a chore.