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I truly look forward to the new harvest each fall. In particular, I am more and more attracted to the newer northern New England cranberry growers, on in Maine and one in northern Vermont, as the quality and size of the berries are far superior to the berries found in plastic bags at the grocery store. When I find a good batch of cranberries, I usually buy them and freeze them raw and whole in their original containers for use throughout the year. I consider them to be happy little health pills.
When a cranberry grower picks for market, there is usually a bog involved. However, bogs only augment the ease of harvest and have little to do with the actual growing of the plant and fruit. In fact, modern bog flooding is relatively recent, popularized only in the past 200 or so years. Originally, hand harvesting was the way to acquire this brilliant ruby prize.
You can grow cranberries in your own garden. They make a great edible ground cover, are as easy to grow as blueberries and share the same genus.
American cranberries are one of the only three native fruits that are grown for mass market, the other two being blueberries and Concord grapes. The plant, Vaccinium macrocarpon is hardy to Zone 3. This means that they can grow in almost any of the lower 48 states, but are grown mostly in northern tier states, as they do enjoy a period of cool dormancy.
This berry was used by native Americans in many ways and these uses were shared with early Europeans who migrated here. The Native American mixing of these tart berries with maple syrup and heat is where cranberry sauce originated. The original users of this berry did not grow them in bogs. They were hand-harvested, dry, from the low-lying fields where they formed massive plant communities.
It is no surprise that the early farming of cranberries took a foothold in Cape Cod. Glaciers left many natural deposits and shallow bogs that became acidic and peaty. These were the best circumstances for cranberries.
While on Cape Cod this past summer, it became clear to me how cranberries were such a dynamic part of the lifestyle and survival of those early European inhabitants. Local historical museums are filled with information about early cranberry business (and later, the cannonball manufacturing that came from the iron ore found in the bogs). Whaling was big business, and cranberries, loaded with vitamin C, were one of the most portable and best guards against scurvy, a common ailment on long voyages.
Back in those early times, the cranberry plants grew in vast flat areas. Entire towns would come out to harvest them, by hand, in the fall. The first recorded cranberry enterprise utilizing bog methodology started in Dennis, on the Cape, and an industry soon followed. Now cranberries are marketed worldwide.
Not only do I like the fruit, but I enjoy the plant of Vaccinium macrocarpon. They are low growing semi-evergreen subshrubs that make very large mats. The leaf is diminutive, but the branching tends to
sprawl like vines. They can have a 7-foot spread that can be pruned. American cranberry is quite long-lived; there are plants in Massachusetts thought to be 150 years old.
If you want to grow cranberry plants, preparation is key. If grown with good care, one could expect around a pound of berries for every 5 square feet of a well-established planting. They make a great ground cover under blueberries, as they prefer the same soil requirements. Cranberries grow in relatively shallow soil, so 8 inches is the deepest you would need to dig. Raised beds would be great for cranberry growing.
Let’s say you wanted to grow a manageable 4-foot-by-4-foot bed: Amend the ground in that area for an acid soil by adding 2 bales (3.8 cubic feet) of peat moss. Mix in bone meal (¼ pound), Epsom salts (½ cup), rock phosphate (½ pound) and blood meal (½ pound). Plants can be placed 18 inches apart. Water consistently throughout the summer. Fastidious weeding would be indicated as they dislike competition.
The fruit is borne on the many short upright stems that pop up every year along the vine. There are three to five flowers per year per branch, so you want to foster these branchlets as much as possible. The plants bloom and set fruit in July. Berries will ripen and should be picked well before temperatures hit 30 degrees in the fall. Cranberries benefit from having about half an inch of sharp sand applied on top of them every 4 years. This allows for rooting along the vine, which encourages more uprights. Be careful not to use too much nitrogen fertilizer year to year, as this spurs too much green growth and fewer berries.
Here is a good website for growing cranberries: www.cranberrycreations.com.
American cranberry is not an easy to find plant. I recommend 3-year-old plants. While you can find 1-year-old starts online, they will not give fruit for three or more years. Obtaining older plants is not extremely hard. Go to a good local nursery and ask about them.
I like the Vaccinium macrocarpon WSU, sold by Vanberkum Nurseries (www.vanberkumnursery.com), a wholesale nursery that also lists the various local nurseries that carry their plants. A special order at your favorite nursery in spring will bring cranberries to you.
Liz Krieg is a longtime horticulturist. She lives in Bethel.