Tearthumb is a common name for a group of annual vining plants within the genus Polygonum, notable for the small, sharp spines covering the stems, which "tear the thumb", leading to the common name. The spines are used for climbing, and can puncture the leaves of plants being used as supports.

Tearthumb is a common name for a group of annual vining plants within the genus Polygonum, notable for the small, sharp spines covering the stems, which "tear the thumb", leading to the common name. The spines are used for climbing, and can puncture the leaves of plants being used as supports.