I was just planting some sugar cane next to my base, when I missclicked and planted it underwater. Instead of being immediately broken by the water next to it, the sugar cane just stayed there.

Steps to reproduce:

1. Get sugar cane
2. Find some water body, that's at least 2 blocks deep
3. Plant the sugar cane on a block that has water placed diagonally down from it (Just like normally, but water is also on the same y level as newly planted sugar cane)