Is my crabapple tree dead? It is, isn't it?

[SPedigrees]

This may not be anything you done wrong. The pictured flowering crab apple tree looks to be healthy in 2020 and is of good size. So I would say it was happy and didn't drown where you planted it.

However generally speaking non grafted crab apples are short liveed 10 to 15 years and they die back. But they do root sucker profusely. Keep an eye out this spring for sprouting root suckers.

Since it's a crab apple it's most likely not grafted, and is most likely on its own roots (commonly called a root cutting). Select a root sucker to grow into a new tree. I would leave it in place to grow into a new tree. You can dig and transplant the other suckers or cut them off at ground level if you don't want any more crab apple trees.

Mother Nature killed my tree; I had nothing to do with it!

My state suffered serious and unprecedented flooding this past summer. Farmers lost their crops, houses and businesses were destroyed and washed away. The state was declared a federal disaster area, and I feel very fortunate that my only loss was a single tree. It rained constantly for an entire month. My couple acres of open mowed land were squishy when you walked on it, and my tree's roots were submerged in water for the entire month of august. It literally drowned.

Most ornamental crabapple trees are not grafted, as you suggested, but this was a 'profusion' variety whose semi-weeping character was the result of grafting. Thus I was aware that if I did not keep the suckers cut, it would revert to a non-weeping form. That was then, but now it and its suckers have gone to that great orchard in the sky.

 

[SPedigrees]

After you take it down, plant forget-me-nots. They love wet feet,

Thanks, that's a good suggestion. I may do so. In the same vein, I ordered a water-loving Joe Pyeweed plant from Bluestone Perennials that will arrive in Spring. That spot is fit only for aquatic plantlife! With the warnings of continuing adverse weather events, it may flood again, but the willows (which share this spot) will be fine at least.