Q.Why Did My 2 Yr Old Weeping Willow Suddenly Change To Upward Vase Shape?
VWould it have been affected by road salt from plows in winter? I’m in Concord NH area, and bought it from a local nursery, & I heard the employee who planted it call it “a trash tree”.

Certified GKH Gardening Expert
I'm afraid your tree has reverted to the root stalk. That means the desirable top of the tree died and the root stalk took over. This can happen with grafted trees. Here is more:
https://www.gardeningknowhow.com/garden-how-to/gardening-by-zone/zone-5/zone-5-weeping-trees.htm
https://www.gardeningknowhow.com/ornamental/trees/willow/planting-weeping-willow-trees.htm