I have a wild mexican plum on my property and I looked it up and the leaves are edible so looks like I have an additional salad green. It unfortunately doesn't produce fruit, I suspect not enough sun. Regardless there is so much abundance all around once you explore outside the programmed box.
Discussion
It appears hackberry leaves are edible, I started adding them, 4x the iron of spinach, 20x the calcium as kale and 20% more potassium than dates. Not that I am hung up on numbers but for others to evaluate. These things grow like crazy around here. Everybody wants to get rid of them.
