Youngberry is a complex hybrid between three different species from the genus Rubus, the raspberries, blackberries, and dewberries of the rose family. The berries of the plant are eaten fresh or used to make juice, jam, etc.
Byrnes M. Young, a businessman in Morgan City, Louisiana, who loved science and plants, had an ongoing correspondence with Luther Burbank, who had created the 'Phenomenal' blackberry–raspberry hybrid. While he had no success growing either loganberries (another blackberry-raspberry hybrid) or 'Phenomenal' berries, Young crossed the 'Phenomenal' with the Austin-Mayes dewberry that was better adapted to his area. This produced ‘Youngberry’ in 1905, which was then released in 1926.
While the youngberry is not grown much in the U.S., it is grown in Australia, New Zealand and South Africa and was a parent of the commercially successful olallie blackberry and a grandparent of the marionberry.
Like its 'Phenomenal' parent, it is a hexaploid.