It is true that these trees cannot survive having roots constantly wet.  Also, I cannot see where the trunks meet the ground but they are grafted trees and the graft must be above ground level.  It looks like you have allowed a sucker to grow several feet on one or maybe both trees.  They have not been in the ground very long so the thing to do would be to dig them out, prepare a good planting site for them and then plant at the proper level.  Open the related links in this publication and follow the directions.  It will be worth it to have healthy trees instead of one that slowly dies.  https://extension.umn.edu/how/planting-and-transplanting-trees-and-shrubs