Rubus × 'Brazos' is a vigorous, erect, and heavily thorny blackberry cultivar released in 1959 by the Texas A&M University breeding program. It was developed as a specialized, complex hybrid specifically designed to thrive in the hot, low-chill climates of the Southern United States. The cultivar represents an F2 generation selection derived from a foundational cross between the Lawton blackberry, an old high-quality erect blackberry variety, and 'Nessberry', a complex hybrid itself containing a mix of wild dewberry (Rubus trivialis) and red raspberry (Rubus idaeus) parentage. This precise genetic combination allowed 'Brazos' to merge the sturdy, self-supporting upright architecture of traditional blackberries with the intense heat tolerance and low chilling requirement of native southern dewberries.

The fruit of 'Brazos' is exceptionally large, firm, and acidic, displaying a glossy black finish that transitions to a deep matte purple when overripe. While its high tartness means it is less frequently favored for fresh consumption, its robust structural integrity and concentrated flavor make it an industry standard for processing into preserves, cobblers, and commercial syrups. Due to its high adaptability and aggressive yield capacity, 'Brazos' serves as a crucial parental reference line in modern pomology, passing its low-chill traits and robust growth habits down to prominent successor cultivars like 'Kiowa', 'Rosborough', and 'Apache'.