When the wind howls as it drives the snow, growers in the Great Lakes region are reminded of how their harsh climate makes successful berry production a challenge. Although new cultivars with better heartiness are constantly being developed, old timers relied on stalwart fruits known to shrug off such nasty weather, such as currants and gooseberries.
According to Dr. Robert Tomesh , University of Wisconsin Extension horticultural expert, currants and gooseberries are an oft-overlooked berry crop for the Great Lakes region.
"These are underutilized crops with great potential in Wisconsin. They are very winter hardy and frost-tolerant as flowers and fruit," he said during the November Brown Bag horticultural program, broadcast across Wisline to Extension offices around the state.
Gooseberries are very important staple in Europe, Tomesh said, valued over the centuries for their healthy attributes, which include a hefty dose of vitamin C and easy keeping in dried or stored form.
Currants rank higher in popularity than goose berries and bear their fruit on racemes, while gooseberries grow individually and have picker-challenging thorns.
Both plants grow as bushes. "That's a very good thing for backyards where large fruit trees are not practical," Tomesh pointed out. "As small shrubs, they can be included in the home landscape, perhaps instead of Spiraea or potentilla; and birds aren't as big a problem as with other fruits, especially with the newer currants."
Tomesh's experience with currants has been greatly enhanced during his journeys through Russia over the past several years, where flatbreads and fruit breads are baked with lots of currants in the mix. "Very tasty," he added.
In general, currants prefer cool well-drained soil in the pH range from 5.5 to 7.5. Sandy soil can be amended by adding peat moss or bark chips for a mulch that will retain moisture.
At Hancock Research Station, mulched currant plants performed wonderfully and were extremely productive, Tomesh said. "It (mulching) is a very easy way to grow these plants," he noted.
Weed control is essential. Tomesh advises keeping the planting site tilled for one season before planting, explaining that cultivating the site on a weekly or biweekly basis will bring up weeds and knock the overall population down.
Select a planting site that will endure. "These are long-term plantings", Tomesh said, since currant and gooseberry bushes will live and be productive for 10 to 20 years or even longer.
There are 150 species of currants and gooseberries across the United States, Europe and Asia. Native Americans enjoyed the currants and gooseberries that they found growing in areas around lakes where the fishing was good, Tomesh reported, while European black currants were introduced to America around 1680.
Among gooseberry varieties, Tomesh likes the pale pink Pixwell for its ease of picking and serious productivity. "I have picked two and three gallons off a single plant," he said.
The bright red Poorman is another older, good, very productive variety, while Welcome offers large, red berries on semi-thornless branches. Notable newer varieties include Hinnomaki Red, while Invicta is a mid-season variety that sports large, greenish to purplish fruit.
Among red currants, Tomesh favors Red Lake for its palatability and mild nature. "This one is very tasty and can be eaten right off the bush," he said, noting red and white currants, such as the disease-resistant Imperial, make excellent jelly, jam and pancake syrup.
Although not as productive as black currant or gooseberry bushes, red currants like Red Lake will still produce several quarts of fruit each year, he added.
Black currants, including the newer, very productive Ben series, are not as palatable as red currants for fresh eating. They are better used for jellies, jams and wine where they are prized for the color and flavor they add. "Black currants are very good when they're really ripe, but it is an acquired taste," Tomesh explained, noting the cooking process breaks down the "off" flavor.
Gooseberry plants tend to be larger than currant bushes. Some gooseberry varieties will grow to heights of five feet and can be quite thorny, Tomesh noted, while currants grow about four feet tall. The plants usually do better in clay soils than in sandier soils, and best in silty loam or clay loam.
Tomesh suggests buying one-year-old plants from a reputable nursery, spacing plants about five feet apart, and using a starter fertilizer that is high in phosphorus, such as 5-25-5. Spreading a full cup around each plant will help develop a strong root system.
Currants and gooseberries are easy to propagate by layering. Simply pin stems to the ground, covering them with earth or mulch, and the plant will send up multiple shoots, Tomesh said, noting he's taken 30 layered transplants off a single mother plant.
Gooseberries and currants are hardy plants, capable of handling temperatures of -40 and -50 without problems and have hardy flowers. Although individual plants are self-fruitful, planting two or more currants or two or more gooseberries should provide a more abundant set of fruit.
Tomesh recommends one cup of 5-10-10 fertilizer per plant per growing season. Apply one-half cup in the spring before flowering and another half-cup in mid-June, spreading the fertilizer out to 1 foot from the base of the shrub to nourish the feeder roots.
If bark mulch is used, get the fertilizer down below the covering by making four or five holes with a shovel and putting fertilizer in each hole, Tomesh recommended.
Avoid deep cultivation, he added, which can damage roots and encourage unwanted suckers; and provide at least an inch of water a week per plant, which tallies about five gallons of water. The ripening fruit will remain on the plants for two or three weeks for ease of harvesting.
Pruning gooseberries and currants should be an annual act. Fruit is produced on second and third season's wood, but wood that is four years and older produces less and less, Tomesh said.
With the goal of maintaining nine to 12 canes of productive age, he advises encouraging growth when the plant is first set out, then selecting eight of the healthiest canes per plant and tipping each cane back so it will branch out.
The second year, save three or four new sucker canes, tip all canes, and remove several older canes. Repeat the third year, again saving three or four new sucker canes selected so the entire plant is maintained in a relatively open habit of growth to cut down on disease and insect problems.
"This method of pruning means you will have three or four one-year canes, three or four two-year canes and three or four three-year canes," Tomesh pointed out. Some growers use spray paint, adding a stripe per year to each cane, a method that allows them to easily spot and remove any four-striped, four-year-old cane.