Ribes Regulations in New England
Some New England states regulate aspects of Ribes spp. production within their boundaries due to their role as alternate hosts of White Pine Blister Rust (Cronartium ribicola), a disease that can seriously affect White Pine trees. In order to determine that status and the specifics of any relevant regulations in your state, check the links below:
CT: No regulations at present
VT: No regulations at present
(Descriptive text adapted from the 2013-14 Mid-Atlantic Berry Guide)
Currants and gooseberries are two closely related species within the genus Ribes. This genus is diverse with more than 150 known species and hundreds of cultivated varieties (cultivars). Currants and gooseberries can be easily distinguished by the presence or absence of thorns; gooseberries usually have thorns, while currants do not.
Ribes plants are long-lived perennial shrubs that are cold-hardy, some to USDA Zone 2. Species and cultivars vary in plant size and form but are usually upright to spreading in habit (3 to 6 feet). Disease and insect resistance is variable. The fruit is versatile and nutritious and varies in presentation, flavor, shape, size, texture, and color.
Most cultivated currants are of European origin, though many native North American species also exist. Currant color types include red, white, pink, and black. Plants are thornless and fruit is small (pea sized) and produced and harvested in a grape-like cluster called a “strig.” Cultivars may be classified under several species; yet some debate exists as to which species different types of plants belong. Species are Ribes rubrum (most red currants and some whites), R. petraeum (white), R. vulgare (pink, white, and red), and R. nigrum and R. ussurienses (black). Native currants, sometimes considered more closely related to gooseberries, belong to the species R. odoratum, the Buffalo Currant, with some selections known as Clove Currant (for example, the cultivar Crandall) because of the fragrance of their blossoms. Because of their tart flavor, currants are seldom eaten fresh but are used for processing into juices, jams, and jellies. Black currants are noted for their strong (to some, offensive) odor and astringent flavor, yet they are highly prized in Europe for juice products and their high nutrient content. Vitamin C concentrations can be as high as 250 milligrams per 100 grams of juice, even after 6 months of storage.
Cultivated forms of gooseberries are divided into two major types, European (Ribes grossularia var. uva-crispa) and American (R. hirtellum). European types are native to North Africa and the Caucasus Mountains of eastern Europe and western Asia, while the American types are native to the northern United States and Canada. Within the European types, fruit size varies widely, from pea sized to small egg sized. Color varies widely as well, with fruit colors in shades of green, pink, red, purple, white, and yellow. This diversity is due to the historical popularity of the European gooseberry. Over the past two centuries, hundreds of cultivars have been developed with a focus on prize-winning fruit size and color.
Native American gooseberry species have smaller fruit size and less flavor, but they are more resistant to diseases when compared to European cultivars, which are noted for powdery mildew and leaf spot susceptibility. This problem has limited the culture of most of the European types in this country. However, disease resistance is improving through additional breeding with American types, and several new promising European cultivars have recently been introduced in the United States and Canada. In comparison, most known American cultivars in the trade today have had some historical infusion of European genetics to improve size and flavor, which can be traced to a handful of crosses made in the 1800s. All gooseberry cultivars have varying degrees of thorniness. Fruit is produced in small groups or singularly on stems and are picked individually.
History and Restrictions
In the early 1900s, the federal and state governments outlawed the growing of currants and gooseberries to prevent the spread of white pine blister rust (Cronartium ribicola). This fungal disease attacks both Ribes and white pines, which must live in close proximity for the blister rust fungus to complete its life cycle. Spores of C. ribicola have to move from one host species (e.g. pine) to the other (e.g., Ribes) in order to complete its life cycle. If one host is absent or highly resistant (immune), the disease does not proliferate. Most black currants (Ribes nigrum) and white pines (Pinus strobus) are extremely susceptible, and red currants and gooseberries exhibit varying degrees of susceptibility. There are some commercially available cultivars of black currant that are highly resistant (immune) to infection by C. ribicola. See more about this in the 'Choosing Cultivars' section below.
Although the federal ban was rescinded in 1966, some northern states still prohibit the planting or cultivation of black currants. Check with your state’s Agriculture Department to find out the status of these regulations (and see the links above).
Some black currant types, such as the cultivars ‘Consort’, ‘Crusader’, and ‘Titania’ are hybrids that are resistant to the blister rust fungus. In some cases, they can be planted in areas where other currants and gooseberries are not permitted.
Ribes are a very diverse genus with hundreds of different varieties that differ in plant size, form, fruit flavor, shape, texture, color and hairiness. While most are hardy to Zone 3 or Zone 4, a few are hardy to Zone 2. Several types of interest include:
Red currants (Ribes rubrum, R. sativum and R. petraeum): Fruits range in color from dark red to pink, yellow, white and beige, and they continue to sweeten on the bush even after they appear to be in full color. Popular cultivars include 'Cascade', 'Detvan', 'Jonkeer van Tets', 'Red Lake', 'Rovada', 'Tatran', and 'Wilder'. Many people consider ‘Rovada’ to be the best red currant cultivar. Plants are dependable, vigorous, late ripening, and very productive, bearing long-stemmed clusters of large red berries that are easy to pick.
White currants: (Ribes sativum) A type of red currant, white currant cultivars are sold less frequently by nurseries. ‘Blanka’ is most commonly available. Berries are large and mild in flavor with a pale yellow color. Most people prefer ‘White Imperial’ or ‘Primus’ if they are available.
Black currants (Ribes nigrum): Black currants are the type most associated with culinary products and flavorings. As a group they are more susceptible to infection by White Pine Blister Rust. Cultivars such as ‘Consort’, ‘Crusader’, 'Ben Sarek', and ‘Titania’ are immune or resistant to this disease.
Jostaberries (Ribes x nidigrolaria): Jostaberries can be used for fresh eating or in culinary products. Until recently only one cultivar, 'Jostaberry', was available. Recently another has been released, 'Orus 8'.
Gooseberries: There are two types of gooseberry plants -- American (Ribes hirtellum) and European (Ribes uva-crispa). Cultivars of the American type are smaller but more resistant to mildew. They tend to be healthier and more productive. American cultivars include ‘Poorman’, ‘Oregon Champion’, ‘Hinnonmaki Red’, ‘Hinnonmaki Yellow’, ‘Captivator’, and ‘Pixwell’. The fruits of the European cultivars are larger and better flavored and include ‘Invicta’, ‘Leveller’, ‘Careless’, ‘Early Sulfur’, ‘Catherina’, ‘Achilles’, and 'Tixia™'. 'Tixia™' has the advantage of having fewer and softer thorns than many of the others.
Sources of gooseberry and currant plants can be found at: http://www.hort.cornell.edu/fruit/mfruit/gooseberries.html
Site Selection and Soil Preparation
Unlike most other fruit crops, currants and gooseberries tolerate partial shade and prefer a cool, moist growing area. Northern slopes with protection from direct sun are ideal. Planting along the side of a building or shady arbor is suitable as well.
Avoid sites with poor air circulation, which increases the incidence of powdery mildew. Sloping ground alleviates this condition. Also avoid light-textured, sandy soils. Rich, well drained soils that have a high moisture holding capacity are best. Incorporate organic matter (compost, peat, or manure) to improve the soil, particularly if it is somewhat sandy. The ideal soil pH is about 6.5.
Purchase strong, well-rooted plants from a reliable nursery, selecting either one- or two-year-old vigorous stock. Because currants and gooseberries begin growth very early in the spring, you should plant them in the early fall or very early in spring, before the plants begin to grow.
Before planting, remove damaged roots and head back the tops to 6 to 10 inches. Do not allow the root systems to dry out. Set plants as soon as possible in properly prepared soil, slightly deeper than they grew in the nursery. Firm the soil around the roots. Space plants according to the vigor of the cultivar, keeping in mind that plants are more vigorous on very fertile soil. As a general rule, plants should be spaced 3 to 5 feet apart in the row with 8 to 10 feet between rows.
Trellising gooseberries increases air circulation (decreasing disease problems), makes fruit easier to harvest, and allows you more plants in less space. Gooseberries are easily propagated through tip layering or stool bedding (mound layering).
Currant and gooseberry plants are heavy nitrogen feeders. To give the plants a healthy start, work manure into the soil before planting. Annual top-dressings of composted manure are beneficial as well. If plants are not vigorous, lightly broadcast about .25 to .5 pound of 10-10-10 per plant. Avoid fertilizers containing muriate of potash (potassium chloride).
Mulch keeps the soil cool in the summer, retains moisture, and controls weeds. Spread 2 to 3 inches of mulch around plants and replenish it yearly. Suitable mulches include straw, lawn rakings, composted manure, compost, wood chips, or similar materials. Grass clippings make excellent mulch. If you use fresh straw or sawdust, you may need to apply nitrogen fertilizer because these high-carbon mulches tie up nitrogen while they decompose.
Remove any flowers so that plants don’t develop fruit during their first season of growth. Expect a light crop the second year and a full crop by the third. Currants and gooseberries ripen in June and July, depending on cultivar. Berries do not drop immediately upon ripening, so they usually can be harvested in one or two pickings. Currants can be picked in clusters, and gooseberries are picked as individual fruits. Expect mature plants to yield about 90 to 150 pounds per 100 feet of row. Wait for fruit to turn color before picking. Gooseberries come off easily when they are ripe. Currants require some trial and error to determine the right time.
Prune currants and gooseberries when the plants are dormant in late winter or early spring. Remove any branches that lie along the ground as well as branches that are diseased or broken. Ribes species produce fruit at the base of one year old wood. Fruiting is strongest on spurs of two and three year old wood.
After the first year of growth, remove all but six to eight of the most vigorous shoots. At the end of the second growing season, leave the 4 or 5 best one-year-old shoots and up to 3 or 4 two-year-old canes. At the end of the third year, prune so that approximately 3 or 4 canes of each age class should remain. By the fourth year, the oldest set of canes should be removed and the new canes allowed to grow. This system of renewal ensures that the plants remain productive because young canes always replace those that are removed. A strong, healthy, mature plant should have about eight bearing canes, with younger canes eventually replacing the oldest.