
Black knot is the signature: elongated black swellings that look like burnt sausage wrapped around twigs and branches, girdling and killing everything beyond them one limb at a time. Distinguish that slow limb-by-limb loss from actual structural failure — bark sloughing in patches off the main stem, gumming or sawdust at the base, and a crown thin everywhere at once means the tree is finished, not merely infected.
Nobody plants it — birds do. It arrives in fence lines, back corners, and along privacy screens and goes unnoticed until it is 40 ft over the neighbor's garage, and because it is one of the most ice-vulnerable hardwoods growing here, it turns into a quote after almost every ice event.