I purchased two Pumpkin Ash seedlings from Mail Order Natives - they arrived in small plugs of earth, keeping the roots intact. I planted them on November 9th 2019 at the back of the yard. Interestingly the leaves are serrated which does not match the descriptions in guide books - they are definitely Ash trees however, as the leaves are opposite on the stem.
In early April 2020, the two Ashes were leafing out. The image on the right is from April 11th.
On May 10th both Ash trees are still growing vigorously. I am not convinced these are really Pumpkin Ash trees, and from guidebooks and internet sources, they may actually be Green Ashes.