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KEY CONCEPTS
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BRAMBLES
Raspberries and blackberries are referred to as brambles. Brambles are good candidates for home fruit production. The fruit of these crops deteriorates within days after picking, making homegrown superior in taste and freshness to commercially grown berries. Brambles produce fruit the second year after planting.
Raspberries and blackberries are perennial plants with biennial growth and fruiting habits. Roots of these plants are cold-hardy and continue to produce above-ground growth from year to year. New canes, called PRIMOCANES, are biennial in that they live two seasons. In the second year they are called FLORICANES because they flower, bear fruit and then die.
Each year new primocanes are produced, ensuring future berry production. New canes form at the base of the crown on black raspberries, certain purple raspberries and thornless blackberries. These do not spread.
Red and yellow raspberries and thorned blackberries form buds randomly along the roots, which results in spreading. The following illustration shows a red raspberry's growth pattern over two years.
There are other differences between red raspberries and other brambles. Generally, thornless blackberries and certain purple and black raspberries are less winter-hardy than red raspberries. Red raspberry buds can tolerate temperatures of -30o F or lower without injury. However, a few hours of over 40o F in the spring can break dormancy of reds. If a hard frost follows, plant injury and bud kill can result.
Blackberries are cold-hardy to -10o F. The plants regrow, but fruit production is greatly reduced. To avoid winter injury, choose the site carefully.
Choose a site that is sunny and away from frost pockets. To combat the winter damage that occurs when temperatures fluctuate, choose a north slope or site on the north side of a windbreak or building. Winter shade will keep raspberries from breaking dormancy too early.
Raspberries can be red, black, purple or yellow. Know the particular cultivar chosen; otherwise, incorrect cultural practices may interfere with fruit production. Recommended cultivars are listed in Fact Sheet 1421, Reference Fruit.4.
Most types of raspberries and blackberries produce one crop. However, some raspberries produce two crops, one in spring and another in fall. This type is called ever-bearing or fall-bearing. All brambles are self-fruitful and produce fruit without cross-pollination.
Plants that are certified disease-free ensure a good start and an abundant crop over the years. Reputable nurseries and mail-order companies offer certified stock. However, this guarantee does not mean that plants are immune to diseases. Stock from friends or companies that do not guarantee disease-free stock can result in plant loss and contaminated soil where brambles and other susceptible crops cannot be grown for years.
Brambles can remain productive for 20 years or more. Protect the investment of time and money by choosing recommended cultivars and quality plants.
Bramble root systems develop in the upper 10 to 20 inches of soil. Brambles should be grown in a sandy loam soil that contains 3% to 4% organic matter, has good fertility and provides good drainage. Raspberries grow best in a soil pH of 5.8 to 6.5, but will grow and produce in many different soils. Use a soil test as a guide before applying lime or fertilizers.
Avoid areas where tomatoes, potatoes or eggplants have been previously grown. These plants carry disease-causing organisms that also infect brambles. Red raspberries are more disease resistant than black or purple.
Newer cultivars of black raspberries have been developed with greater disease resistance. Avoid locations within 300 feet of wild raspberries and blackberries. Wild brambles are less disease resistant than hybrids and may harbor disease which can be spread.
Plant in early spring, March or April, if soil is not overly wet. Fall planting is acceptable but not preferred. Apply a mulch to fall-planted stock to prevent heaving due to the soil freezing and thawing. Keep mulch away from the stems.
Plants ordered by mail will be short sticks or canes a few inches long with a fibrous root system. The plants will be either bare-root or planted in a pot. Bare-rooted stock will be packed in moist peat moss or some other sterile, moisture-retaining material. Soak bare-rooted plants in a bucket of water 20 to 30 minutes before planting. Move plants from the bucket directly to the planting hole.
Dig a hole 1-1/2 times the size of the root mass. Fan out roots in the hole and fill in soil to the soil line around the canes. Space each plant according to the recommendations in Fact Sheet 1421, Reference Fruit.4. Water immediately after planting, and every 2 or 3 days for the first week if no rain occurs.
Several factors affect fruit production. Cane diameter and length, soil fertility and condition, amount of winter damage, and amount of sunlight and water affect yield. Pruning eliminates old canes, thins plantings to allow air circulation and sunlight penetration, and lessens competition for available nutrients and moisture.
A few years after planting raspberries, sprouts may come up several feet into the lawn or other garden areas. To discourage brambles that sucker (red and yellow raspberries and thorned blackberries), place a barrier, such as galvanized sheet metal 12 inches into the soil. Otherwise, you must cultivate and remove the suckers as they spread.
A trellis system can be used to keep canes and berries off the ground, making care more manageable. Use a #9 gauge wire strung in two parallel lines at a height of 30 inches. Because of growth habit, red and yellow raspberries and thorned blackberries are usually grown in a hedge or row. Black and purple raspberries and thornless blackberries are grown in hills.
Ten to 14 days after planting, apply 1 pound of a 10-10-10 fertilizer per 100 feet of row (1/4 cup per plant). Repeat this application rate 1 month later. For maximum fruit production, plants must grow as rapidly as possible in early spring.
After the first year, apply fertilizer in early spring before growth begins. Repeat the application in May. Apply 2 to 3 pounds of 10-10-10 fertilizer per 100 feet of row (1/2 cup around each plant).
Because brambles have 75% of their roots in the top 12 inches of soil, they can be quickly water stressed. Supplemental watering is especially critical during blossoming, fruit ripening and fall flower bud development. About 1 to 1-1/2 inches of water per week is needed from rainfall or supplemental watering.
Avoid wetting foliage to reduce risk of disease infection. If overhead watering is the only available method, apply water early in the day so leaves dry quickly. Directional watering wands can be used to apply water to soil. Soaker hoses and drip systems can also be used to avoid wetting foliage.
Mulching is recommended for weed control and moisture retention. A 2- to 3-inch layer of shredded leaves, straw, sawdust or other material is suitable. Keep mulch away from the stems. Mulch keeps the stems moist and increases the chances of disease infection.
Root competition from nearby weeds or other vegetation can drastically affect fruit production. When cultivating for weeds, applying fertilizers or adding organic matter, remember that brambles have very shallow root systems. Some mulches remove nitrogen from the soil, so be sure to supplement with nitrogen when appropriate.
Pruning is done to remove weak canes, make remaining canes manageable, increase air
circulation and light penetration, and to promote growth of more fruit-bearing lateral branches. Cut all bramble canes down to the ground after they have finished bearing. Dispose of old canes as soon as possible to reduce pests and disease. Other pruning practices vary, depending on type of bramble grown.
Red raspberries are pruned twice a year: first in spring and again after harvest. The spring pruning removes all weak canes and cuts back remaining canes to 3 to 4 feet. The second pruning is to remove all canes which have borne fruit.
Black and purple raspberries are pruned 3 times a year. Dormant pruning before growth begins means cutting back lateral branches to 8 to 10 inches. Remove the top 3 to 4 inches of new shoots as they grow in June. The last pruning cuts of the season remove floricanes after harvest.
The ever-bearing cultivar 'Heritage' and yellow raspberries are most easily maintained by mowing the canes back to a height of 1 inch in spring and harvesting only a fall crop.
Check Fact Sheet 1421 for pruning practices of each bramble type, Reference Fruit.4. An example of how to prune a red raspberry bush is given in the following illustration. This method is not advised for black raspberries.
[illus. from 1421]
Research has demonstrated that bees affect 90% to 95% of raspberry pollination. The home gardener should avoid pesticides that kill bees when brambles are in flower.
Most pesticide treatments on brambles can be made when a problem is detected. However, this approach requires frequent inspection of the planting to identify problems before they become serious.
Many of the diseases and pest problems of brambles can be controlled by good cultural practices. Early identification and removal of problems is essential. Entire plants infected with some virus diseases must be removed.
Most of the fungi that infect brambles overwinter in old canes that were infected during the previous growing season. Cut and remove these canes to control these diseases.
Thinning, proper watering and avoiding wounding canes help prevent disease. Good drainage stimulates vigorous growth and reduces the impact of insects and diseases. Avoid shady sites. Regular picking of fruit will help control certain insects: sap beetles, wasps, fruit flies and Japanese beetles.
The following insects can injure brambles: raspberry crown borer, Eastern raspberry fruitworm, picnic beetles, Japanese beetles, aphids, spider mites, rose scale (where roses and brambles are grown in close proximity), raspberry cane borer, and leaf miner.
Bramble diseases include anthracnose, cane blight, spur blight, septoria leaf spot, grey mold, powdery mildew, orange rust, crown gall, verticillium wilt and various virus diseases. Aphid and nematode control is essential in controlling several viral diseases.
For identification and treatment of specific problems, refer to the Ortho Problem Solver and Ohio State University Extension Bulletin 780, "Controlling Diseases and Insects in Home Fruit Plantings."
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