Hill System for Planting Black Raspberries

Physiology

• Red raspberries produce new canes from nodes that form all along the roots, which explains why they often form an impenetrable patch. Black raspberries, on the other hand, form new canes only from nodes on the bottoms of 2-year-old canes, called floricanes. Black raspberries form a clump that does not spread into the surrounding area. This physiological difference is the reason for the different training methods between the two varieties.

Planting

• Plant black raspberries 4 to 8 feet apart in rows at least 8 feet apart. When the primocanes begin to grow, give them an application of fertilizer in the form of 1/4 cup of ammonium nitrate scattered around each black raspberry plant.

Supporting

• Provide a supporting structure to keep the canes off the ground. A wire trellis formed from posts installed every 20 to 30 feet in the row, with stout wire strung between the posts, is sufficient for supporting black raspberries. Install 5-foot-high posts with one wire fastened 3 feet off the ground and the second wire fastened at the top of the posts. Even though canes will not grow up between the black raspberry plants, the space between them will be used up when fastening the canes to the trellis wires.

  Another method of supporting black raspberries is to pound a 4-foot stake into the ground near each plant when initially planting them. The canes are then tied to the stake for support.

Pruning

• Black raspberries are summer-bearing, which means they produce their crop in late summer on 2-year-old canes called floricanes. After they are finished bearing their crop, cut all floricanes back to ground level. The remaining canes are canes that have grown during the current season; they are called primocanes.

  The following spring, thin the canes that are in their second year of growth, which are now called floricanes, to the strongest four or five on each plant and remove all others. Cut back all of the side branches to about 12 to 18 inches long. Tie the floricanes to the supporting trellis, spacing them as evenly as possible.

  Do not remove new shoots that emerge from the base of the plant as the growing season progresses. These new shoots are primocanes and will bear fruit the following year. Pinch out the growing tip when the primocanes are about 2 feet high; this will encourage them to branch out and subsequently produce more fruit.