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Brambles

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General Information

The success of a bramble planting is highly dependent upon its location. The site should have full exposure to sunlight and good air circulation. It should also be somewhat protected, however, as brambles are quite susceptible to winter injury. Temperatures below -20˚ F will injure most fruit buds above the snow line. Colder temperatures, especially if no snow cover is present, can kill canes to the ground, or damage roots, causing plants to die in the early summer when not enough water can be taken in to support them.

The soil should be well-drained; brambles will not tolerate “wet feet.” Wet soils encourage the spread of Phytophthora root rot which will destroy brambles. Do not plant brambles where potatoes, tomatoes, peppers, strawberries or eggplant have recently been grown, because these crops carry Verticillium, another root rot fungus which can infect brambles. Avoid planting brambles near any wild brambles. Wild raspberries and blackberries harbor insects and virus diseases which will spread to cultivated plants. If possible, destroy all wild brambles within at least 600 feet of your planting.

Always obtain raspberry plants from a reputable nursery which certifies their plants to be virus-free. Raspberries are best planted in the early spring. Plant your rows at least 8 feet apart, preferably 10 to 12 feet apart to ensure adequate air circulation, as well as room for spraying, harvesting and pruning operations.

Raspberry plants are shallow-rooted and thus are poor competitors for water and nutrients if weeds are present. A 3 to 6” layer of mulch will help to conserve soil moisture and inhibit weed growth. Coarse sawdust, wood chips or bark make good mulching materials. Pine needles work well, but need replenishing more frequently. Mulching of raspberry plantings is not without risk. The use of a permanent mulch may delay fruit ripening and plant hardening-off in the autumn, increasing the risk of winter damage. Mulching is not recommended after the first year on heavy soils due to the risk of Phytophthora. Mulch is also a haven for rodents that feed on plant roots and canes. Baiting is recommended where mulch is used.

Proper pruning is a crucial part of pest management for raspberries. In the late winter, remove second year canes and thin out weak, spindly first year canes. Thin out the remaining canes, leaving only those with good height, large cane diameters and no symptoms of winter injury, insect or disease damage. Everbearing varieties (e.g., Heritage) may be completely mowed down each year in early spring before growth starts. This will result in only the primocane (Fall) crop being harvested. For an early summer crop on everbearing varieties, remove weak, spindly first year canes in the winter and thin out remaining canes. The new fruit crop is borne on the cane below where fruit was the previous fall. 

Plant rows should be narrowed to a width of 2 feet or less. When finished, there should be no more than 4 to 6 canes per linear foot of row remaining for red raspberries, and 4 to 8 canes per crown for blackberries, black and purple raspberries. Canes which have been cut should be removed from the planting and destroyed. Pruning in this manner will greatly reduce the incidence of most raspberry cane diseases by increasing air circulation and reducing disease inoculum. Check with your Cooperative Extension office for details of proper varieties and cultural techniques for brambles, or see NRAES 35, Raspberry & Blackberry Production Guide available through New England Extension Fruit Specialists. See source page at end of this guide for more information on ordering the Raspberry & Blackberry Production Guide.

Table 37. Recommended optimal soil characteristics for growing brambles.
Soil Characteristic Desirable Range*
pH 5.8 - 6.5
Organic matter 4 - 6%
Phosphorus 20 - 30 ppm
Potassium 120 - 180 ppm
Base Saturation >3.0
Magnesium 100 - 150 ppm
Base Saturation >5.0
Calcium 1000 - 1500 ppm
Base Saturation >50.0
*Desirable range will vary with soil types (sand, silt, or clay), soil organic matter, and pH.
Foliar nutrient Normal range
Table 38. Standard Foliar Ranges for Brambles
Nitrogen 2.0 - 2.8 %
Phosphorus 0.25  -0.4 %
Potassium 1.5 - 2.5 %
Calcium 0.6 - 2.0 %
Magnesium 0.6 - 0.9 %
Boron 30 - 70 ppm
Manganese 50 - 200 ppm
Iron 60 - 250 ppm
Copper 6 - 20 ppm
Zinc 20 - 50 ppm
   
Year Sandy Loamy Clay Sandy Loamy Clay

Table 39. Post-Plant Nitrogen Recommendations for Brambles

Irrigated                                           Non-Irrigated

FALL-BEARING REDS (NO SUMMER CROPS)*
1 40 30 25 35 30 25
2 80 70 60 70 65 50
3+ 120 100 90 90 80 70
SUMMER-BEARING REDS
1 35 20 25 30 25 25
2 55 50 45 45 40 35
3+ 80 70 60 60 50 40
SUMMER-BEARING BLACKS AND PURPLES
1 30 25 25 25 20 20
2 45 40 35 35 30 25
3+ 60 50 45 45 40

30

 

Note: Rates should be adjusted according to leaf tissue analysis.

*Split the recommended amoutn into two applications with half at cane emergence and half in mid-July

Table 40. Number of bramble plants per acre at different spacings.
Feet between plants in a row Spacing Between Rows    
8 FEET 10 FEET 12 FEET
1.5 3630 2904 2420
2 2,722 2,178 1,815
3 1,815 1,452 1,210
4 1,360 1,090 907
5 1,090 870 726
6 907 726 605
8 680 544 453