Sugar Maple - All Questions

When to Prune a Maple Tree Many gardeners are confused about when to prune a maple tree. In late winter, when the days are warm and the nights are cold, root pressure causes sap to flow from any wound made in the bark of the tree. This makes it look as if the tree is suffering. However, maple tree pruning in winter generally won’t hurt a mature tree. You would have to remove an entire limb for the loss of sap to negatively impact a fully grown tree. If the tree is just a sapling, however, loss of sap may cause problems. You can avoid this issue if you wait until summer to prune maples. Once the leaf buds open, the sap is no longer under pressure and won’t leak out from pruning wounds. For this reason, many gardeners say that the best time for pruning maples is in summer after the tree is fully in leaf.

Read more at Gardening Know How: Maple Tree Pruning – How And When To Prune A Maple Tree https://www.gardeningknowhow.com/ornamental/trees/maple/maple-tree-pruning.htm

Sugar maple is listed as juglone tolerant, so you may plant near the black walnuts.