'Niwot' fall bearing black raspberry released

Niwot black raspberry (US PPAF) - Photo by Pete Tallman

There is good news for Front Range small fruit lovers this year. Black raspberries (note we are not talking blackberries, a different crop) have not been recommended for this area before now. Recommendations have been to only grow red and yellow raspberries because of cold hardiness issues with black raspberries.

Longmont amateur plant breeder, Pete Tallman, has released the first fall bearing black raspberry recommended for the Front Range. Niwot has at least zone 5 hardiness and possibly greater.

Why is this a big deal? Now we can grow black raspberries that will fruit on first year canes in the fall. Before now the black raspberries available fruited on second year canes (summer types) and those canes were not hardy enough to reliably survive into the second year here. With Niwot, you can grow and harvest all in one growing season, cut canes to the ground in late winter and repeat.

Niwot was selected to be self-fruitful (no second variety required for pollination) and have good production of large fruit with small seeds. Fruit ripen in late August to September. Unfortunately the plant does have thorns.

There is very limited 2014 availability from Henry Field's Nursery that is selling the plant under the name 'Sweet Repeat'. Plants of Niwot won't be widely available until 2015 from Nourse Farms, Inc.

Raspberry pruning time

It's time to finish pruning last year's raspberry canes before new growth begins. The fall types that bear in August on first year canes are pruned to the ground every year in late winter.

Based on information from Cornell University, the best time to prune is from December through early March. Before December, the plant is still moving energy from plant leaves to the crown and pruning canes removes valuable carbohydrates. After early March, carbohydrates have already moved from the crown to buds that may be removed in pruning.

Prune canes as close to the ground as possible so that buds break from below the soil surface. If you leave a stub, buds break on the stub and resulting canes are poorly anchored and subject to breaking in winds. In the photo right, two canes near the head of the pruning shears have been correctly pruned at ground level. The four inch stub at the right of the photo should be pruned again closer to the ground.

Gather all pruned canes, rake fallen leaves and remove all plant materials from the site. This eliminates overwintering aphids and other insect and disease organisms.

While the single crop produced by the fall bearing type raspberries is smaller than traditional summer bearing types that bear fruit over two years, management is much easier. Rather than pruning the two year canes of summer types after bearing in late summer from among new, one year canes, all canes of fall types are easily pruned to the ground in late winter. Eliminating detailed pruning is only one advantage of fall types. Also eliminated are cane thinning, support and tying, cold injury of buds on overwintering canes, overwintering insects and damage from rabbits or voles. For all these reasons the fall bearing type raspberries are recommended.

For more information on growing raspberries and other small fruit, attend one of my classes (see schedule right column).

Photo credit: Pruned raspberry canes, Closeup of pruned canes, Disposal of raspberry prunings - All credit Carl Wilson

Raspberry pruning

Red raspberries are very hardy and grow well along the Front Range. Black and purple raspberries do better in milder climates like the fruit producing areas on the West Slope.

While raspberry clumps are perennial, individual raspberry canes should be removed after they have fruited once. In practice, this means that canes should be pruned out after either their first or second year. The trick is to know which year to prune.

The raspberries you have may be either summer (June) fruiting varieties, or fall bearing plants that produce a late summer/fall crop. Summer bearers flower and bear fruit on canes that grew the previous year. Once they fruit, those canes won’t produce a crop again and should be removed. Recommended summer bearing varieties are Latham, Boyne, Laura and Honey Queen.

Fall varieties bear fruit on new growth produced in the summer. Those canes will produce a light early summer crop the next summer. After that, the canes should be removed. Fall bearing canes can be cut down to the ground in early spring if an early crop of fruit isn’t wanted. Fall bearing varieties include Heritage, September Red, Fall Red, Red Wing, Amity, Pathfinder, Trailblazer, Plainsman, Perrone’s Red, Caroline, Autumn Bliss, Goldie and Anna.