- This blackberry is the latest release from the University of Arkansas. Ouachita, pronounced WAH-shitah, is a very upright growing vigorous thornless blackberry. Plants can be self-supporting when primocanes are tipped at 42 inches. However, trellising may be needed to keep a full crop from leaning out of the row. Fruit quality is excellent. Berries are firm, sweet and larger than Navaho and Arapaho, but smaller than Apache, averaging 6 grams each. Fruit matures about 7 days before Navaho. Yields are high, sometimes exceeding those of Apache and Navaho in most tests and Arapaho consistently. Shown to be disease resistant under most conditions.