Wisconsin Cranberries and Pollination
The American or large-fruited cranberry, Vaccinium macrocarpon, is indigenous to the North American
continent. It can be found along the northern portion of the United States from Maine to Wisconsin, and
along the Appalachians to North Carolina.
Cranberries are a vital part of Wisconsin's agricultural economy as they provide more than 1/2 of the
nation's total cranberry crop from 18,000 acres of beds. Another 160,000 acres are given to adjacent
wetlands, woodlands, and uplands. Huge networks of ditches, dikes, dams and reservoirs are a common
sight in Wisconsin to support cranberry production.
Wisconsin was responsible for 59% of the nation’s cranberry population with the production of
4.67 million barrels. Wisconsin’s gains roughly 4,000 jobs and $1 billion from cranberry production.
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Native Americans did not cultivate it (called sasemineash by the Narragansett tribe), they
gathered berries and used them in pemmican, a mixture of dried meat or fish and berries
that was pounded into a pulp, shaped into a cake and dried in the sun.
Native Americans were the first to make it into a sweetened sauce using maple sugar. The berries were
also eaten raw. Cranberries were used as a poultice for wounds and when it was mixed with cornmeal
it was an excellent cure for blood poisoning. The juice was used as a dye to brighten the colors of their
blankets and rugs. The early settlers called the fruit "craneberry" because before the flower expanded,
its stem, calyx, and petals resembled the neck, head, and bill of a crane. It may have also come about
because cranes found it to be one of their favorite foods. Through usage, the fruit eventually came to
be called cranberry.
Many Wisconsin Native Americans eventually developed an itinerant economy. Putting in gardens at their
homesteads, they harvested strawberries, cherries, potatoes, beans, and cranberries for white growers,
returning home at intervals to care for and harvest their own gardens.
The cranberry flower hangs upside-down with the flower opening facing the ground. The pollen and nectar are
tucked up inside the flower. Bumble Bees are well suited to pollinate this type of blower because they use
buzz pollination. Buzz pollination is performed by making the flower vibrate, causing the pollen
to drop down and cover the bee with pollen and facilitating pollen transfer. Because of the ability of Bumble
Bees to buzz pollinate, each individual Bumble Bee is a highly efficient cranberry pollination.
Approximately 30% of Wisconsin cranberry growers buy managed Bumble Bee colonies and place them on
the marsh at a rate of 1 to 2 colonies per acre.
Honey Bees do NOT buzz pollinate and, for that reason, each Honey Bee is less efficient at removing or
transferring pollen than a Bumble Bee. However, the presence of approximately 40,000 Honey Bee worker
bees per hive during bloom means that Honey Bees often do the bulk of the marsh pollination.
Approximately 90% of Wisconsin cranberry growers rent commercial Honey Bee colonies during bloom.
These are typically placed on the marsh at a rate of 2 to 3 hives per acre.
In addition to the use of commercial pollinators, over 400 species of native wild bees exist in the Midwest and
many of them visit and pollinate cranberries. In fact, many Bumble Bee species are also native to Wisconsin.
These native Bumble Bees along with other species of will bees are likely to be present in varying degrees
on most cranberry marshes.
Flight Periods for Native Wild Bees Around The Cranberry Marsh
For hundreds of years cranberry harvesters picked the wild berries by hand. Starting in the 19th century,
the cranberry rake — a hand-held tool with a large comb at one end and a basket at the other —
increased production. The rake allowed leaves and stems to pass through the tines of the comb while
collecting the berries in the basket.
During harvest the marshes were flooded with 6 - 10 inches of water to make the berries float to the surface,
where seasonal workers wielding cranberry rakes collected them. Each fall, large bunkhouses in Tomah
and Wisconsin Rapids filled with migrant workers. Native American workers would set up camp on the
grounds of some of the larger marshes to work as pickers. Workers were paid 75 cents per bushel, and
in 1875 pickers averaged two bushels per day.
The berries were then brought to a warehouse for cleaning, grading for quality and storage. At the end of a
long day of picking berries, workers might look forward to dancing and music before retiring early to prepare
for another day's labor.
During the 1945 season, German prisoners of war confined in Wisconsin worked in the cranberry bogs near
Wisconsin Rapids. The prisoners worked in the marshes all summer, weeding the beds, digging drainage
ditches and assisting with the harvest.
Around 1950 harvesting began to be mechanized. In 1949, 96 percent of Wisconsin cranberries were harvested
with hand rakes, but by 1956 two-thirds were harvested mechanically. Commercial production in Wisconsin
began near Berlin in Green Lake County in the early 1850s. The center of the industry later moved to marshes
around Tomah, Warrens and Wisconsin Rapids. Today almost all berries are harvested by machine.
Named for their discoverer Eli Howes in 1843. For many decades this was the standard
variety of late berry. They were bigger, rounder, on stockier vines and ripened around the first week
of October. Howes are a hard berry, demonstrating more resiliency against frost and better keeping
quality (fruit rot).
Discovered by Cyrus Cahoon in 1847, it’s a small, dark, blackish-red berry ripening
during the first two weeks of September. They are uniform in size and were once favored because they
could be harvested before the hard frost of fall set in. They are not particularly productive and some
feel that each upright bears fruit only bi-annually.
A very popular hybrid cross of ‘McFarlin’ and ‘Potter’ (a sub-variety of ‘Searles’ which
is itself a wild heirloom dating back to 1893 in Wisconsin), this type dominates the market in cultivation.
‘Stevens’ was so named by H. F. Bain in 1940, in Whitesbog, New Jersey. The fruit ripens a bit earlier than
that of ‘Howes,’ with a deep red color and lots of seeds. Vigorous vines produce high yields, and the fruit
is juicy but low in pectin — perfect for commercial processing as well as home use.
This native wild type was selected for cultivation and named in 1901 by D. R. Burr in
Berlin, Wisconsin. This is an early variety known for being very productive, with large, deep red fruit.
It is often grown commercially via clones of the original wild plant, or used in breeding to create new
Cranberries should be grown between zones 3 and 5. Cranberries can be planted at various times throughout
the year, depending on the age of the plant.
Cuttings and seedlings can be planted throughout autumn, from October to early November.
They can also be planted in springtime, from the middle of April to the end of May.
3-year-old rooted plants — which are still actively growing — can sometimes be
planted in summer, provided they are purchased in pots.
When it comes to soil, cranberry plants have unique requirements -- they need soil with a low pH
value and a high level of organic matter. Before planting, wet the soil thoroughly (but do not saturate
it). You can do this by misting the plot with the garden hose, mixing the soil periodically to
It's important to be aware that cranberry plants do not start to produce fruit until their 3rd or
4th year — so whether you choose to plant cuttings or seedlings will depend on how
quickly you want fruit.
Cuttings. If you choose to plant cranberry cuttings, plant them in the prepared wet soil,
leaving approximately one foot of space between each plant. The root ball of each plant should
be about 2 inches below the surface of the soil.
Seedlings: If you choose to plant 3-year-old seedlings, leave approximately 3 feet of space
between each plant.
Soon, your cranberry plants will start to put out runners that grow along the ground. The
runners should grow until they fill and cover the bed. If they do not, you can fertilize your
cranberry bed with a high-nitrogen fertilizer. Only use fertilizer if runners are struggling to grow.
Too much high-nitrogen fertilizer may cause overwhelming growth.
From the 3rd year of growth onwards, you will need to prune the cranberry plants each spring
to control the runners and encourage uprights. You can do this by combing the cranberry plot
with a landscape rake, until all of the runners are going in the same direction. This makes it easier
to identify the longest runners and cut them back. Do not prune the existing uprights.