Prime Jim is a primocane-fruiting; thorny, ERECT blackberry. It was developed by University of Arkansas in 2004. ( Patent #16989). Fruit size: floricane fruit average 5 g; primocane fruit vary by location grown, from 3 to 10 g in various trials. Flavor/sweetness: good, similar to other thorny varieties; soluble solids (percent sugar) averages 8%.Yield: floricane yields comparable to floricane-fruiting thorny and thornless varieties such as Apache and Ouachita; exceeds Arapaho in floricane yield. Primocane yields vary greatly by location, from very high in the Willamette Valley of Oregon to very low at Hope, Arkansas. Maturity date: floricane fruit ripens beginning approximately June 3 at Clarksville, Arkansas, and fruiting extends for about four weeks. Floricane ripening season is near that of Arapaho. Primocane fruit begins ripening approximately July 17 at Clarksville and Sept. 1 in Oregon. Primocane fruiting can continue until frost depending on summer and fall temperatures. Fruit development to maturity may not be completed in more northern areas of the U.S. Hardiness similar to other Arkansas thorny varieties.  1 gal. Size.