[8] It is an erect bramble, typically 1.5 metres (5 feet) but occasionally rarely over 2.4 m (8 ft) high, with single shrubs approaching 2.4 m or more in breadth, although it usually forms dense thickets of many plants.

[8] Many mammals eat the fruit, including elk, foxes, American black bears, rabbits, raccoons, opossums, squirrels, mice, and chipmunks, and deer will browse the young canes.

The mammals and birds that eat the fruit then disperse the seed in their droppings, enabling the plant to spread to new locations.

[12] Concentrations of R. allegheniensis increase greatly after events that destroy taller shrubs and trees and thus permit more light into the understory, such as fires or widespread blowdown.

[10][13] These populations often decline in later years as the tree seedlings sheltered by the blackberry canes grow and reduce the amount of light reaching the lower levels.