- Some Good Choices Available for Fall Raspberries in Michigan
- By Eric Hanson
Michigan State University
- Primocane-fruiting raspberries produce fruit in the fall on the ends of the one year-old ‘primocanes’. They are also referred to as everbearers, because they can produce one crop in the fall on the primocanes and more fruit on the same canes the following summer.
The fall fruiting habit offers the advantages of production after traditional summer raspberries are done, and also reduces pruning costs. If only fall berries are desired, plants can be pruned by mowing each spring. This is much easier than the selective hand pruning required for summer bearing raspberries.
Primocane-fruiting varieties have been available for over a century, but older types had inferior fruit quality and/or late fruiting seasons. Commercial production of fall raspberries in the Midwest really began after the variety Heritage was released in 1969.
Heritage is now the most planted raspberry worldwide, and accounts for a third of the acreage in Michigan. Although Heritage produces reliable yields of firm, flavorful fruit, it also has weaknesses. First, Heritage begins fruiting relatively late. Harvest begins in late August in southern Michigan, so adequate yields can be picked before the season is terminated by cold weather. North of Lansing, picking may not begin until early or mid-September. Here, early cold weather often ends the season before much fruit is picked. A second weakness of Heritage is that fruit are small.
Several more fall-fruiting varieties have been released over the last 20 years. With support from the Michigan State Horticulture Society Trust Fund, we have tested a number of these in trials in East Lansing (1994-1996) and Benton Harbor (1999-2002).
Varieties tested in one or both trials included Autumn Bliss, Autumn Britten, Caroline, Dinkum, Heritage, Polana, Redwing, Ruby, and Summit. The earliest maturing types (Autumn Bliss, Autumn Britten, and Polana) produce the first ripe fruit almost two to three weeks before Heritage. Caroline, Dinkum, Fallgold, Redwing, and Summit fruit several days before Heritage, and Ruby begins with Heritage.
Of the very early varieties (Autumn Bliss, Autumn Britten, Polana), Autumn Bliss appears to be the most productive, and usually has the largest fruit. Bliss berries have large druplets that do not always adhere to one another, so berries are somewhat crumbly and settle in containers. Berries have a pleasant, mild flavor but are very susceptible to gray mold.
Autumn Britten is newer and not as widely tested as Bliss. In Benton Harbor, Britten produced flavorful, large berries that were more cohesive than those of Bliss, but equally susceptible to rot. Although Britten was less productive than Bliss, it has out-yielded Bliss in other U.S. trials. The third early variety is the 1991 Polish release, Polana. Polana needs further testing because it was only tested in Benton Harbor and one plot was planted late. Polana fruit are bright and glossy and have an intense flavor. The primary concerns with Polana is that canes were very short and yields and size are small. The Benton Harbor test site has a very sandy soil and some growers thought that vigor and yields could be increased by fertilizing Polana more heavily, or if it were grown on heavier soils. Polana berries were relatively susceptible to gray mold.
The mid-season varieties (Caroline, Dinkum, Redwing, Ruby, Summit) are several days earlier than Heritage. Observations in Benton Harbor indicate Caroline is clearly the best of these. Caroline has been vigorous and extremely productive. Berries are medium to large, flavorful, fairly firm, and have a very low incidence of botrytis rot; as low as Heritage.
Dinkum (1992 Australian release) does not appear to have serious faults, but it also has not produced outstanding yields or fruit quality. Redwing was tested only in East Lansing. It is a vigorous, productive, and flavorful variety.
However, berries are smaller, somewhat soft, and difficult to pick because they are hidden by the leaves. Redwing may be a better choice for homeowners than for commercial use. Summit was only tested in East Lansing. It was fairly productive, but inadequate berry size and susceptibility to disease preclude its use here.
Ruby (1989 release from New York) begins ripening at the same time as Heritage. Ruby produced acceptable yields in both East Lansing and Benton Harbor; the berries were the largest of any variety tested. The most serious faults of Ruby are high gray mold susceptibility and a mild to weak flavor. Ruby berries can also be crumbly at times.
In summary, good choices for growers in southern Michigan or areas with extended growing seasons are Autumn Bliss, Caroline and Heritage. Some growers report that Autumn Britten also performs well. In more northern locations, choose from the earlier ripening types Autumn Bliss and Autumn Britten.
Caroline may be sufficiently early to succeed where the season is somewhat short. In these marginal areas, also consider hastening the harvest by placing floating row covers, such as Reemay, over the rows once the snow melts in the spring. Place a row cover, such as Reemay, loosely over the raspberry row so the primocanes can grow beneath it, then remove it when the canes are a foot tall.
This encourages early cane growth, which translates into earlier fall fruit. In more southerly areas, the earliest of the summer fruiting raspberries may provide a nice crop of fall fruit. In Benton Harbor for example, Prelude produces a nice primocane crop beginning in early to mid September. Nova has also produced fall berries.
