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Berries and Grapes

Berries and grapes are ideally suited to many of Idaho’s growing areas. Regardless of where you live in the state, there are small fruits that you can grow successfully. As with all other crops, however, success largely depends on selecting varieties that are well adapted to your climate and soils.

Berry and Grape Grower’s Guides

Blackberries are suited to Idaho’s warmer growing regions, preferably in USDA Plant Hardiness Zone 6, although they can be grown with some success on a few Zone 5 sites. www.usna.usda.gov/Hardzone/hzm-nw1.html. They are best adapted to southwestern Idaho from Mountain Home west and in the Lewiston and Orofino areas of northern Idaho. Even in these locations, select cold hardy, early ripening varieties. You can grow blackberries in other areas, but expect occasional to frequent winter injury and you may have difficulty getting the fruits to ripen before fall frosts.

Blackberries grow best on moderately acidic, deep, well drained soils but will tolerate neutral soils that are somewhat heavier and less well drained than are required for raspberries. If soil drainage is a problem on your site, grow blackberries in raised beds that are about 12 inches high and about four feet wide.

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Growing Raspberries and Blackberries in the Inland Northwest and IntermountainWest

Blackberries

Expected Yield: 6 to 7 pounds per hill
Age to maturity: 3-4 years
Productive life: 8-12 years
Hardiness: +5 to -20°F, depending on variety
Optimum pH: 6.2 to 6.8
Erect varieties: 5 feet apart in rows 10 to 12 feet apart
Trailing varieties: 5 feet apart in rows 8 to 10 feet apart

Erect Blackberries

Blackberries are divided into two types: erect and trailing. Erect blackberries are generally more cold hardy than trailing types and are better adapted to Idaho. Even the most cold hardy blackberries, however, cannot tolerate temperatures lower than about -20 to -25 °F. Erect blackberries can be grown free-standing, although one or two trellis wires can help keep the bushes more manageable, particularly in snow country. For a list of recommended thorny and thornless blackberry varieties, click here.

Trailing Blackberries

Trailing blackberries (also known as dewberries) include such varieties as ‘Marion,’ ‘Logan,’ ‘Hull,’ ‘Bababerry,’ ‘Tayberry,’ and ‘Tummelberry.’ Trailing blackberries are not reliably cold hardy in Idaho growing conditions. Most are injured or killed by winter temperatures around 0 to +5°F. Although not recommended for commercial production in Idaho, gardeners in the warmest locations can grow trailing blackberries by giving them some extra attention. Details on how to do this, as well as how to select, plant, and care for blackberries in Idaho is in our free guide, Growing Raspberries and Blackberries in the Inland Northwest and Intermountain West.

Blueberries are among the most popular fruits for home and market gardening. Both highbush and lowbush blueberries are native to North America and are used fresh or processed into jams, syrups, compotes, fruit leathers, and pastries. Blueberries are firm and hold their quality well both on the bush and in refrigeration. The fruits are easy to freeze and retain their quality when frozen. Blueberry crops can be harvested two to three years after planting, and reach maximum production in six to eight years. Several types of blueberries are available to gardeners. In Idaho, select varieties adapted to USDA Plant Hardiness Zones 4-6. As a general rule, for long-lived plants like blueberries, select varieties one, or preferably two, zones hardier than your location.

Besides producing fruit, blueberries are attractive in landscapes. The compact bushes are easy to prune and produce brilliant orange to red foliage in autumn. The fruit attracts birds and other animals, making blueberries valuable in wildlife-attracting landscapes. Depending on the variety, mature bushes range from eighteen inches to ten feet in height.

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Growing Blueberries in the Inland Northwest and Intermountain West

Blueberries

Expected yield:

  • Half-highs 1 to 3 pounds per bush
  • Highbush 8 to 20 pounds per bush

Age to maturity: 6 to 8 years after planting
Productive life: more than 50 years
Hardiness: -15 to -30°F, depending on variety
Optimal pH: 4.2 to 5.2
Exposure: full sun
Plant spacing:

  • Lowbush: 1 foot between plants
  • Half-highs: 2 to 3 feet apart in rows 6 to 8 feet apart
  • Highbush: 4 to 5 feet apart in rows 8 to 10 feet apart
Selecting a Site

Blueberries require acid soils, which greatly limits where they can be grown in Idaho. A soil pH between 4.2 and 5.2 is ideal (pH 7.0 is neutral). Blueberries can be grown, with some challenges, on sites where the pH is as high as 6.0. Blueberries suffer from iron chlorosis on soils with pH values above 6.0 that are common in southern Idaho and scattered throughout the state.

Soils having pH values between 5.5 and 6.0 can be acidified by incorporating sulfur into the soil one or two years before planting blueberries. Soil acidification is not cost effective for large sites or when soil pH values are above 7.0. For small scale production on sites with heavy soils, poor drainage, or alkaline soils, blueberries can be grown in raised beds or containers filled with potting mixes or amended soil.

Sites with cool, moist, well drained loamy sand, sandy loam, and loam soils containing around 3% or more organic matter are best for blueberries. Coarser soils dry out too easily and clay soils inhibit root growth and encourage root rot. Production on silt loam soils is possible, but can be challenging due to poor water drainage. Muck soils and boggy areas are unsuitable for blueberries unless you can create raised beds at least 14 inches above the soil surface. On some sites, increasing soil drainage with buried drainage tiles can improve blueberry production.

While blueberries survive in partial shade, you need full sun exposure to develop good fruit flavor and maintain high yields. Blueberries grown in the shade become tall, spindly, and unproductive, creating bushes that are unattractive and do not tolerate snow loads well.

Varieties

Blueberries are among the most cold hardy fruits, but there are differences in varieties. The most cold hardy blueberries tolerate temperatures of -35°F or below, and many varieties survive temperatures between -20 and -25°F. Rabbiteye and southern highbush blueberries are not reliably cold hardy in Idaho.

Currants, gooseberries, and jostaberries are quite easy to grow in Idaho. These fruits in the genus Ribes were once grown commercially in the United States and Canada. All of them, particularly black currants, are grown in Europe and New Zealand today. American fruit growers are also once more considering currants and gooseberries for commercial production.

Currant and gooseberry production, particularly black currants, has largely been restricted in the United States because these crops can serve as alternate hosts of white pine blister rust, which has caused major problems for the timber industry. At one time, efforts were even made to eradicate all domestic and native gooseberries and currants in the country. Although these eradication efforts failed, the development of new selections of blister rust resistant white pine, currants, and gooseberries has reduced the problems associated with the disease, and restrictions on Ribes cultivation are being relaxed. There are currently no restrictions on growing currants or gooseberries in Idaho.

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Growing Currants, Gooseberries and Jostaberries in the Inland Northwest and Intermountain West

All Currants and Gooseberries

Cold hardiness: 20 to -31 F
Optimal pH: 5.8 to 6.8

Black Currants

Expected yield: 5 pounds per bush
Age to maturity: 3 to 4 years
Productive life: 15 years or more
Spacing: 8 to 10 feet apart 4 to 5 feet apart in rows

Red and White Currants

Expected yield: 5 to 8 pounds per bush
Age to maturity: 3 to 4 years
Productive life: 15 to 20 years or more
Spacing: 8 to 10 feet apart 4 to 5 feet apart in rows

Gooseberries

Expected yield: 5 pounds per bush
Age to maturity: 4 to 5 years
Productive life: 15 to 20 years or more
Spacing: 8 to 10 feet apart 4 to 5 feet apart in rows

Red and white currants are genetically the same, differing only in fruit color. These colorful, tart fruits can be eaten fresh, make excellent jellies and syrups, and brighten up dishes when used as garnishes. Black currants were developed from different species and lack the bright, translucent skins of their red and white cousins. Except for the American black currant variety ‘Crandall,’ black currants have a strong flavor that makes them best suited for processing into jellies, syrups, and other foods. Black currant juices and drinks are rich in vitamin C and other beneficial compounds, and are tremendously popular in Europe. Black currants are also rich in anthocyanins, phenolic acids, and antioxidant capacity, making them particularly healthy additions to the home garden.

Currants are noted for their cold hardiness. You can grow them successfully in USDA Plant Hardiness Zones 3b to 7.

Gooseberries range from white to yellow to green to red in color and vary in size, from small marbles to plum-sized fruits. They resemble grapes in appearance and flavor, and make good substitutes in the garden in locations too cold for grape production.

Jostaberries are hybrids between gooseberries and black currants. The very vigorous, thorn-free canes bear dark purple fruits about the size of medium-sized marbles. The fruits lack the strong black currant flavor and can be used fresh or processed.

Selecting a Site

Ribes are adapted to cool, moist conditions and are noted for their cold hardiness. They do not, however, tolerate high temperatures well, especially when combined with intense sunlight. They can be grown in partial shade, but yields are better in full sun. For reliable fruit production, your site should have 120 to 140 or more frost-free days. Mountain and valley locations in northern and central Idaho are excellent for currants. High temperatures combined with intense sunlight and droughty, alkaline soils can make production difficult in parts of southeastern and southwestern Idaho. In these areas, consider growing currants, gooseberries, and jostaberries in partial shade, preferably screened from the afternoon sun.

Ribes grow best on deep, organic-rich, well-drained soils with good water-holding capacity and a pH of 5.8 to 6.8. They tolerate heavier soils and poorer drainage than raspberries, blackberries, or blueberries, although they grow and produce better when the soils are well drained. On heavy soils, alkaline soils, or poorly drained sites, grow these crops in raised beds at least twelve inches high and three to four feet wide.

Pests and Diseases

Several pests and diseases can make Ribes production challenging in Idaho. Powdery mildew damages stems, leaves, and fruits, and can kill highly susceptible plants. In general, European gooseberries are the most susceptible Ribes crop, followed by black currants and red and white currants. Jostaberries are quite resistant to powdery mildew. Starting in early spring just as the new leaves are emerging, applications of sulfur sprays every two weeks can help control powdery mildew. Stylet crop oil can also help control mildew. Dormant applications of lime sulfur and/or Bordeaux fungicides help control the disease, as does raking up and disposing of leaves and prunings. By far the most effective strategy is to select varieties that are resistant to powdery mildew.

Avoid problems with white pine blister rust by planting resistant varieties. If you live within one mile of native or ornamental five-needled pines, plant only varieties known to be resistant to blister rust. For information on controlling currant and gooseberry diseases, click here.

Several pests can seriously damage currants, gooseberries, and jostaberries if left unmanaged. Imported currant worm, currant fruit fly, and various stem borers are the most common and serious pests. For information on identifying and controlling these pests, click here.

Varieties

Red and white currants are generally considered self-fruitful, but can benefit from cross pollination on some sites and in some years. For reliable production, plant two red or white currant varieties together. White and red varieties can pollinate one another. Black currants are at least partially self-sterile and you should plant two varieties close together to ensure good fruit set. For black currants, the variety ‘Titania’ is the best blister rust-resistant variety available in the United States. Use ‘Consort,’ ‘Coronet,’ or ‘Crusader’ black currants as cross pollinators.

Because they are highly susceptible to powdery mildew, European gooseberries can be very challenging to grow in Idaho. American varieties, although generally producing smaller fruits, are much easier and more reliable to grow here.

Only a few jostaberry varieties are available. ‘Josta’ is the most common. Other varieties include ‘Jostaki’ and ‘Jostagrande (a.k.a ‘Jogrande’). The latter two should be planted together to ensure cross pollination. Josta is partially self-fruitful and can be grown alone.

Pruning

Most currants, gooseberries, and jostaberries are pruned while they are dormant during the late winter and early spring, but you can prune any time after the leaves have dropped in the fall. Fall pruning improves air circulation around bushes during wet fall, winter, and spring months, and can decrease disease problems. Remove unwanted canes as close to the ground as possible, and always remove drooping canes that lie close to the ground. Canes are normally not shortened or headed back. Be careful while pruning red currants, white currants, and gooseberries not to damage the spurs. Most of the fruit for these crops is borne on short spurs on two and three-year old canes. Black currants bear most of their crop at the base of one-year-old shoots and spurs on two-year-old wood.

With mature red and white currant, gooseberry, and jostaberry bushes, your goal should be to keep three or four strong, new canes per plant each year, and to remove an equal number of the oldest canes. In this system, mature plants have nine to twelve canes after pruning, three to four each of one-, two-, and three-year-old wood. Remove all wood that is four years old or older.

Black currants are more vigorous than other currants and gooseberries, and you normally leave more canes. As a general rule, leave ten to twelve vigorous canes per bush. If the bushes are very vigorous, leave a few more canes. About half of the canes left after pruning should be one-year-old, with the remaining half being vigorous two-year-old canes. Remove all canes that are more than two years old.

Weed Control

Mulch your plants to provide weed control. Four inches of sawdust mulch around currants and gooseberries helps control annual weeds, maintain soil moisture, and keep soils cool. Rake mulches away from plants in early spring to allow the soil to dry and warm. Cold, wet soils retard plant growth. Ensure that quackgrass and any other perennial weeds are eradicated before applying mulch.

Grapes are an immensely popular fruit crop with gardeners worldwide and Idaho gardeners are no exception. Idaho has commercial table and wine grape industries, located mostly in southwestern Idaho and, to a lesser degree, in and around Lewiston in northern Idaho.

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Backyard Grapes
Selecting Grape Cultivars & Planting Sites in Idaho

Pruning Backyard Grapevines in the First Three Years

Grapes

Expected yield per vine: 6 to 10 pounds
Age to maturity: 4 years
Productive life: 30+ years
Hardiness (depending on variety): +5 to -25F
Optimum pH: 6.0 – 7.0
Spacing: 5-7 feet apart in rows 10-12 feet apart

GrapesGiven a suitable site, grapes are easy to grow, but more labor intensive than most berry crops due to the amount of pruning, trellising, and training required. Grapes tolerate a wide range of soils, from rather heavy to sandy and acidic to alkaline soils. Best production is on deep, well drained, and neutral to slightly acidic soils.

Climate creates the greatest challenge for grape growers in Idaho. Generally speaking, three types of grapes are available: European (vinifera), American, and hybrids of the two. European grapes are popular for wine, juice, raisin, and table use, but are the least cold hardy of the three types. Examples are ‘Chardonnay,’ ‘Pinot Noir,” and ‘Riesling.’ European grapes are typically cold hardy to about -5 to +10°F and can be difficult to ripen in areas with cool summers. European grapes are risky in all areas of Idaho, but can be grown successfully in the warmest regions of southwestern Idaho in USDA Plant Hardiness Zone 6. Even here, expect vines to be injured or killed by freezing temperatures occasionally. Mulching the base of the trunks with 12 inches of soil or compost from late fall through early spring can help prevent the entire trunk from being killed during cold winters.

American grapes are the most cold hardy types, tolerating winter temperatures of -15 to -25°F. Examples include ‘Concord,’ ‘Delaware,’ and ‘Niagara.’ American varieties are used fresh and for jams, jellies, juices, and wines. American grapes are the most reliably cold hardy throughout the state, normally being considered hardy in USDA Plant Hardiness Zones 5 and 6,  but can be difficult to ripen in northern, central, and southeastern Idaho. Also, grapes have not performed well in many parts of northern Idaho where winter temperatures fluctuate dramatically.

Hybrid grapes represent crosses between European and American species. They are intermediate in cold hardiness, ranging from -15 to +5°F, and include some of the earliest ripening varieties. These varieties are generally used for wines and juices. Examples of hybrid grapes include ‘Aurore,’ ‘De Chaunac,’ ‘Marechal Foch,’ and ‘Verdelet.’ In Idaho, hybrid grapes are best grown in USDA Plant Hardiness Zone 6 and should perform well in the fruit-growing areas of southwestern Idaho and along the lower-elevation Clearwater drainage near Lewiston.

Raspberries are among the most popular and easy to grow small fruits for Idaho gardeners. Depending on the variety, the plants adapt well to a range of soil conditions and can be quite cold hardy. These popular fruits can be eaten fresh or made into jams, jellies, syrups, compotes, pastries, juices, and many other foods. Besides their excellent flavor, raspberries provide vitamin A, vitamin C, and dietary minerals. You can choose varieties that produce a single heavy crop in late spring to mid summer or two smaller crops in late spring to mid summer and again in late summer or early fall.

Download our free how-to guide!
Growing Raspberries and Blackberries in the Inland Northwest and Intermountain West

All Raspberries

Age to maturity: 3 to 4 years
Productive life: 8 -12 years or more
Optimum pH: 6.2 to 6.8

Black Raspberries

Expected yield: 2.5 to 3 pounds per hill
Hardiness: -5 to -10° F
Plant spacing: 3 feet apart in rows 8 to 10 feet apart

Purple Raspberries

Expected yield: 3 to 4 pounds per hill
Hardiness: -15 to – 20° F
Plant spacing: 3 feet apart in rows 8 to 10 feet apart

Red & Yellow Raspberries

Expected yield: 2 to 3 pounds per hill
Hardiness: -20 to – 25° F
Plant spacing:

  • Summer-bearing: 2 to3 feet apart in rows 8 to 10 feet apart
  • Fall-bearing: 2 feet apart in rows 10 feet apart

Raspberries come in four colors: red, yellow, back, and purple. Red and yellow raspberries are the same species, differing only in color, and are the most cold hardy of the brambles. A few varieties tolerate winter temperatures of -20 to -25 °F and many are hardy to -20 °F. Black raspberries belong to a different species and can be injured by temperatures between -5 and -10 °F. Purple raspberries are crosses between red and black raspberries. They are very vigorous, highly productive, and fall somewhere between red and black raspberries in cold hardiness. In Idaho trials, purple raspberries survived winter temperatures of -20 °F with no injury.

Raspberries produce either one or two crops of fruit each year. Summer-bearing raspberries produce a single crop of fruit beginning in late spring to mid summer. Fall-bearing (also known as everbearing or primocane-bearing) raspberries produce a crop in late spring to early summer and another crop in late summer or early fall. Red and yellow raspberries may be either summer- or fall-bearing. All black and purple raspberries are summer-bearing, but some varieties may develop terminal fruits on the first-year canes (primocanes) during exceptionally long, warm growing seasons. By growing several varieties, you can enjoy fresh berries from late spring through late fall.

Raspberries grow best on deep, well drained soils. Although raspberries tolerate a relatively wide range of soil pH values, wet soils can create serious problems with root rot diseases. Red and yellow raspberries are especially susceptible to poor drainage and root rot. Some black and purple varieties are less susceptible. If you have a heavy-textured or otherwise poorly drained soil, grow your raspberries on beds at least 12 inches high and three to four feet wide. For small beds where heavy soils are present, consider mixing sand into the soil in the beds. Do not apply organic mulches to heavy or poorly-drained soils; doing so increases problems associated with cold, wet soils.

Strawberries are one of, if not the most, adaptable fruit crops in the world. These tremendously popular berries are grown from the tropics to near the Arctic Circle. Besides their appeal as fresh fruits, strawberries can be easily processed into jams, jellies, pastries, syrups, fruit leathers, and many other tasty treats.

Download our free how-to guide!
Growing Strawberries in the Inland Northwest and Intermountain West

All Strawberries

Optimum pH: 5.5 – 7.0
Productive life: 2 to 3 years

June-Bearing Strawberries

Expected yield: 0.5 to 1 pound per foot of row during the second and third year
Fruit years: second and third
Spacing:

  • Matted row: 12 to 18 inches apart in rows 36 to 48 inches apart
  • Ribbon row: 4 to 9 inches apart in row 36 inches apart
Everbearing Strawberries

Expected yield: 0.25 to .05 per pound of row during the second and third year
Fruiting years: second and third

Dayneutral Strawberries

Expected yield:

  • Year 1: 0.25 to .75 pound per foot of row
  • Years 2 and 3: 0.5 to 1.5 pound per foot row

Fruit years: first, second and third
Spacing:

  • Matted row: 12 to 18 inches apart in rows 36 to 48 inches apart
  • Ribbon row: 4 to 9 inches apart in row 36 inches apart

StrawberriesStrawberry varieties fall into three categories: June-bearing, everbearing, and day-neutral. June-bearing strawberries respond to the short days of autumn by setting flower buds. In the late spring or early summer of the following year, a June-bearer produces a single, heavy crop of strawberries. Remove all flower blossoms that form during the planting year to encourage strong, healthy plants. Begin cropping your June-bearers the year after planting. Replace beds more than three years old.

Everbearing strawberries also set flower buds in fall, but do so again during the long days of summer. In this way, these varieties bear two moderate crops each year: one in the late spring or early summer and another in the late summer and early fall. Particularly during cool growing seasons, everbearers produce a trickle of fruit throughout the summer. As with June-bearers, remove all flower blossoms that form during the planting year. Replace beds more than three years old.

Dayneutral strawberries set flower buds throughout the spring, summer, and fall. Theoretically, they should bear a continuous crop of fruit from late spring until fall frosts. In actuality, they behave more like everbearers under Idaho conditions, with moderate to heavy crops in the spring and fall, and a smaller stream of berries in between. As is true with the everbearers, cool weather during the summer encourages flower formation and fruiting. Day neutral varieties yield more than everbearers. Remove all blossoms that develop between spring planting and early August. You can begin cropping dayneutral varieties during fall of the planting year. Because they come into production the year of planting, rather than in the second year, yields over the life of the planting are greater than for June-bearers.

Although they are highly adaptable, good site selection, site preparation, and variety selection are critical if you are to be successful with strawberries. The best sites have deep, moist, well drained soils. Sandy loams are best, but most loams are satisfactory if drainage is provided. Strawberries do not tolerate either drought or wet soils well. Commercially, most strawberries are grown on raised beds about 12 inches high and 18 inches wide. This practice is also excellent for home gardeners. For details on planting designs and crop care, download a copy of Growing Strawberries in the Inland Northwest and Intermountain West.

Selecting the right variety for your site is important. Cold hardiness, for example, ranges from slightly below freezing to ­50°F. Resistance to common strawberry diseases also varies greatly among varieties.

University of Idaho Extension

Physical Address:
E. J. Iddings Agricultural Science Laboratory, Room 52
606 S Rayburn St.
Moscow, ID

Mailing Address:
University of Idaho Extension
875 Perimeter Drive MS 2338
Moscow, ID 83844-2338

Phone: 208-885-5883

Fax: 208-885-6654

Email: extension@uidaho.edu

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Barbara Petty