Shrub swamp

Shrub swamps — also called scrub swamps or buttonbush swamps — are a type of freshwater wetland ecosystem occurring in areas too wet to become swamps ("true" or freshwater swamp forest), but too dry or too shallow to become marshes. They are often considered transitional ("mid-successional") between wet meadows or fens and conifer or hardwood swamps.

By some classifications, shrub swamps must have at least 50% shrub cover and less than 20% tree cover. Other definitions specify large shrubs with small trees less than 35 feet (11 m) in height. Creation of shrub swamps often follows a catastrophic event in a forested swamp (flood, cutting, fire, or windstorm). Another route of development is via drained meadows and fens which progress to shrub swamps as a transitional state to forested swamps.