Rubus × 'Brainerd' is a vigorous, semi-erect blackberry cultivar released in 1932 by the USDA in cooperation with the Georgia Experiment Station. It was developed from a cross between the Himalayan blackberry (Rubus armeniacus), an incredibly invasive and productive European species, and an unknown eastern US seedling (possibly a chance seedling called the Georgia Mammoth). This hybridization was a targeted attempt to combine the extreme vigor and drought resistance of the Himalayan parent with the superior fruit quality and cold hardiness of native North American erect blackberries. It represents an early 20th-century milestone in breeding for regional adaptability, particularly for the challenging climates of the American South and Midwest.

The fruit of 'Brainerd' is medium-to-large, deep black, and significantly more flavorful than its Himalayan parent, possessing a balanced sweetness and a pleasant, traditional "wild" blackberry tang. The plant is heavily armed with thorns—a trait inherited from both parent lines—and produces exceptionally long, sturdy canes that require substantial space or a trellis system.