We have this tree in our yard which neither C nor myself remember planting.
Every spring it flowers (right of pic).
Then last spring, I chanced on a tv gardening show, which identified the tree for me: it is a feijoa and the fruit is edible. It is also sometimes called pineapple guava.
I also learned that you need to keep the fruit after they've fallen off the tree and they will ripen fully and soften.
About a month ago, the fruit started falling and we started collecting them.
I had never seen feijoas on sale before.