The presence of long thorns usually makes Prunus nigra relatively easy to identify. The thorns have dull surfaces with small buds (or their scars) along their length. The thorns of the similar Crataegus spp. are shiny and smooth. The buds of Crataegus are usually red and blunt and the buds of Prunus nigra are brown and clearly sharp pointed. The gland tipped teeth on leaves and sepals of Prunus nigra distinguish it from the very similar Prunus americana.

Prunus nigra is less common in Wisconsin than Prunus americana and is more likely to occur in woods, whereas P. americana is more common on sunny sites. It appears to be irregularly distributed throughout most of the state, although not reported from about half the counties. It appears to be rare or absent in several adjacent counties in the northeastern part of the state and in the extreme southern counties.