Blackberries are a native bramble crop of North America that can adapt to a variation of environments. Often found wild along the edges of woodlands, blackberry brambles provide a source of food for animals and birds as well as a nutritious fruit for humans. While some wild blackberries are still thriving in woodland areas in Pennsylvania, a number of thornless cultivars have been established for harvesting purposes that work well in the Pennsylvanian climate.
The native blackberry is a thorned bramble with long canes that grow in semishaded areas. While thorned blackberries are generally not grown as a crop fruit, a number of varieties are being tested in Pennsylvania and other states as a niche market crop. Illini Hardy and Darrow varieties are both types that are winter-hardy with vigorous growth and medium-sized fruit that could grow well in the Pennsylvanian climate.
Thornless varieties have been developed as a crop fruit. While not as winter-hardy as native types with thorns, thornless brambles offer an easier harvest for the home gardener and the professional. Most thornless types are grown in the warmer growing zones of Pennsylvania, including the late-fruiting Navajo, the largest fruiting thornless, Triple Crown and the popular trailing variety Chester.
Most blackberries, both wild and crop-grown, are known as "floricane" brambles, that is, plants that flower and fruit in their second and subsequent years of growth. "Primocane" varieties are newer cultivars that will produce some crop in their first year of growth, a trait most home gardeners want. Prime-Jan and Prime-Jim are both very thorny, first-year fruiters with a tart, medium-sized fruit that's well-suited for jelly production. Test trials are currently underway to determine their hardiness to the Pennsylvanian climate.