This makes them difficult to control, and control measures often require follow-up treatment. Hardy to zone 5, it is moderately easy to grow blackberries in Wisconsin. The majority of the native high-bush blackberries in Wisconsin have long translucent hairs on the lower surfaces of their leaves. Amend the soil with well-draining, rich garden loam. Himalayan blackberry is smooth with the white-grey felt and only a row of hooked thorns running along the underside of the leaf mid-vein. Known by … Wisconsin lies about geographically center in the black raspberry universe, according to a map at the USDA. Like raspberries, blackberries are aggregate fruit , but a tiny portion of the stem stays within the aggregation when the fruit is picked. Blackberries, Wisconsin's most abundant wild fruit. Use equal parts with your existing soil to make a great soil mix. Wild blackberries are able to regenerate from the crown or rhizomes following mowing, burning, or herbicide treatment. Apply manure at a rate of two to three bushels per 100 square feet. Rototill the soil to mix in everything. A black berry, not blackberry.