Cut off any suckers growing from below the graft at the lower end of the trunk.
Young Honeylocusts need supplemental watering when they are first planted, during drought and in late fall before the ground freezes for the winter. Once they are well established, around 5 years old, they need watering only in times of prolonged drought. For information on products see the file on Choosing Watering Equipment
If the tree is in healthy soil, rich in organic matter, there will be no need to fertilize it. A 2 or 3 inch mulch layer of some organic material such as chopped leaves or wood chips will improve the soil as it decomposes over each season. So, in several years a mulched tree will enjoy healthy soil. For more information see the file on Using Mulch
Routine pruning of Honeylocusts is not necessary. You might need to prune out a second leader, or central stem, on a young tree to establish a single strong trunk. Otherwise, pruning is limited to removing injured branches promptly with a clean cut that will promote healing. For more information see the files on Pruning Shade and Flowering Trees and Choosing Pruning Tools