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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

Pruning Small Fruits in Late Winter and Early Spring

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Small fruits commonly grown in home gardens include raspberries, grapes, gooseberries, currants, and blueberries. For maximum production, small fruit crops need to be pruned in late winter/early spring. Proper pruning procedures for raspberries, grapes, gooseberries, currants, and blueberries are outlined below.

Raspberries

The pruning procedures for raspberries are based on the growth and fruiting characteristics of the plants.

Summer-Bearing Red Raspberries

Remove all weak, diseased, and damaged canes at ground level in March or early April. Leave the most vigorous canes, those approximately 1/4 inch in diameter when measured 30 inches from the ground. After thinning, remaining canes should be spaced about 6 inches apart.

Also, prune out the tips of the canes, which have died due to winter injury. Cut back to live tissue. If the canes have suffered little winter dieback, remove the top 1/4 of the canes. Cane-tip removal or "heading-back" prevents the canes from becoming top heavy and bending over under the weight of the crop.

Red raspberries sucker profusely from their roots. Plants should be maintained in a 1- to 2-foot-wide hedgerow using a rototiller or spade.

Fall-Bearing Red Raspberries (Two Crop System)

Follow the same pruning procedures as described for the summer-bearing red raspberries. This pruning option provides both a summer and fall crop.

Fall-Bearing Red Raspberries (One Crop System)

Prune all canes back to ground level in March or early April. While the plants will nnot produce a summer crop, the late summer/early fall crop should mature one to two weeks earlier. Also, total crop yield is typically larger utilizing the one-crop system versus the two-crop system.

Maintain the plants in a 1- to 2-foot-wide hedgerow.

Yellow Raspberries

The pruning of summer-bearing and fall-bearing yellow raspberries is identical to their red raspberry counterparts.

Black and Purple Raspberries

Remove the small, weak canes, leaving only four or five of the largest, most vigorous canes per clump or plant. Cut back the lateral (side) branches to 12 inches in length for black raspberries and 18 inches for purple raspberries.

Grapes

To maximize crop yields, grapevines are trained to a specific system. The most common training system used by home gardeners is the four-cane Kniffin system. The four-cane Kniffin system is popular because of its simplicity. In this Kniffin system, the canes of the grapevine grow on 2 wires, one located 3 feet above the ground and the second 6 feet high.

If utilizing the four-cane Kniffin system, select four canes on the upper wire, two going in each direction. Also, select 4 canes on the lower wire. To aid identification, some gardeners tie brightly colored ribbons or strips of cloth on those canes they wish to retain. All remaining one-year-old canes should be completely removed.

Going back to the upper wire, select two of the remaining four canes (one going in each direction). Prune these canes back to 1 or 2 buds. These short 1 or 2 bud canes are referred to as renewal spurs. The renewal spurs provide the shoots or canes that will produce next year's crop. Prune the remaining two canes on the upper wire back to 8 to 13 buds. The number of buds left on the fruiting canes is determined by plant vigor. If the grapevine is vigorous, leave 13 buds per cane. Leave only 8 buds per cane if the grapevine possesses poor vigor.

Prune the four canes on the lower wire the same as those on the upper wire. When pruning is complete, no more than 60 buds should remain on the grapevine. When counting the number of buds on the grapevine, include both the buds on the fruiting canes and those on the renewal spurs.

Gooseberries and Currants

Gooseberries and currants produce the majority of their fruit on two- and three-year-old shoots. Shoots that are 4 years old and older produce very little fruit. After the first growing season, remove all but 6 to 8 vigorous, healthy shoots. The following year, leave 4 or 5 one-year-old shoots and 3 or 4 two-year-old canes. After the third growing season, keep 3 or 4 shoots each of one-, two-, and three-year-old growth. A properly pruned, established plant should consist of 9 to 12 shoots. Pruning of mature plants consists of pruning out all four-year-old shoots and thinning out some of the new growth.

Blueberries

Blueberry plants are shrubs like currants and gooseberries. Blueberry yields and fruit quality decline when blueberry canes (stems) reach 5 years of age. In late winter/early spring, prune out any dead or diseased stems. Also, prune out canes that are 5 years old and older. Allow 1 to 2 new shoots to develop each year.

Additional information on pruning raspberries and grapes can be found in PM 1706 Growing Raspberries in the Home Garden and PM 1707 Growing Grapes in the Home Garden.

Page References: 
6-7
Year of Publication: 
2007
Issue: 
IC-497 (2) -- February 7, 2007