Can blackberries be successfully grown in Iowa?

The growth and fruiting characteristics of blackberries are similar to raspberries.  The blackberry plant’s roots and crown are perennial, while its stems or canes are biennial.  Blackberry canes are strictly vegetative during the first growing season.  These first year canes are referred to as primocanes.  The following year, these same canes (now called floricanes) flower, produce fruit, and then die. 

In Iowa, the canes of most blackberry varieties suffer extensive winter injury.  As a result of this damage, plants produce little or no fruit.  However, there are two hardy varieties that can be successfully grown in the southern half of the state.  ‘Darrow’ produces large fruit on vigorous, erect, thorny canes.  ‘Illini Hardy’ bears medium-sized fruit.  The fruit are produced on vigorous, erect, thorny canes.  Primocane-bearing blackberry varieties are a new option for home gardeners in Iowa.

The canes of primocane-bearing blackberries don’t need to survive the winter as they produce fruit in late summer/early fall on the current year’s growth. Prime-Jim™ and Prime-Jan™ are erect, thorny plants.  Fruit are medium-sized, conical, soft, good flavored, and glossy black in color.  In Iowa, gardeners should prune the canes of Prime-Jim™ and Prime-Jan™ back to ground level in late winter.