Weeping Willow Cankers

Weeping Willow tolerates wet soil, but that does not protect it from canker fungi after drought, heat, or mechanical injury. Trees that swing from saturated spring roots to summer stress are the ones that most often show dead twigs, discolored bark, and cankers that keep expanding around weakened wood.

Cytospora species cause classic cankers: sunken, often dark lesions that may ooze resin and stop the transport of water beyond the infected area, producing progressive branch dieback. Infected tissue often shows a sharp margin where healthy wood gives way to sunken, discolored bark; that margin and exudation are the fastest way to separate canker from general decline.

Timing matters: active infections and visible dieback usually become clear after warm, dry spells or when a tree has been wounded. For intervention and slower spread, we recommend dormancy pruning and sanitation; the dormant season concentrates cuts when fungal activity is lowest and lets you inspect cambial margins more clearly. Growers who adjust watering to match seasonal shifts see faster recovery in other stress-prone trees, and the same approach helps Salix babylonica.