The apple leaf is fairly easy to identify/ related families as rose or june berry are also edible. There is as much variation in crab apples as in table apples, crabs are “small size apples”. (under 1.5”) About 20% of the named selections at the university arborateum have interesting/ useful tasting tannin. The neighborhood ones I “found“ are prairie fire which have low juice/ high solids and a gravity of 1.095, a pink color, pH mid 3s, in late august a tannin that is astringent/ September a nice bitter and by November/ frost they are fairly mild.
There is another group out there which consists of the variable genetics when domestic apple seeds self seed, these “apple crabs“ are a pot luck of sharps, sweets, bitters, aromatics, pink flesh, russets.
You can graft crabs on apple and apple on crab, sooo if you find interesting apples in fall mark them and in spring graft them on apples in the yard so their easier to get to. Apple bears on second year old wood like grapes.
There is another group out there which consists of the variable genetics when domestic apple seeds self seed, these “apple crabs“ are a pot luck of sharps, sweets, bitters, aromatics, pink flesh, russets.
You can graft crabs on apple and apple on crab, sooo if you find interesting apples in fall mark them and in spring graft them on apples in the yard so their easier to get to. Apple bears on second year old wood like grapes.
I've never known a crab apple to be sweet, either. Maybe it's a regular apple with problems. Either way, I have multiple crab apples and never thought much about them. This year will be different, though.