Brambles - Production Management and Marketing

Bulletin 782-99

Chapter 3 Selection and Care of Plants

Erect Blackberry

Research data does not show any greater yield from erect (thorny) blackberries than from thornless blackberries. Erect types generally do not require a trellis, and the berries are sweeter than thornless. Cold temperatures cause damage to most erect blackberries tested in Ohio; this damage is similar to the damage caused to thornless blackberries.

Setting the Plants

Set the plants at about the same depth as they grew previously. The crown of the plant (the point where the roots and stem join) should be no more than one to two inches below the soil surface. Plants may be set by hand in a furrow or in individual holes. In planting, spread out the roots and firm the soil carefully about them. To prevent drying of roots, carry the plants wrapped in wet burlap or in a bucket of water during the planting operation. Ordinary mechanical transplanters can be adapted for use in setting bramble plants and may be used to advantage when large plantings are established.

Immediately after setting, cut back the tops of red raspberry canes (except transplants) to about six inches. On black and purple varieties, remove the old cane (handle) at the ground line to eliminate a possible source of anthracnose infection. Burn or bury all removed parts.

Dormant black and purple raspberry tips should not be covered too deeply with soil at first or they may be smothered. A good procedure is to cover them with an inch or two of soil when planting and to add soil gradually as the shoots grow, so that the roots are finally covered with four to five inches of soil. Apply a recommended herbicide and irrigate the planting during the first several weeks after planting if there is no rainfall. Be sure the plant roots do not become dry after planting.

Fertilization

After the soil has been prepared and the plants have been planted, the amount of fertilizer for optimal production and winter hardiness is of major concern. In general, phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) should not be required at this time if these were applied before planting according to soil test results and recommendations. If considerable minerals, manures, and compost were applied, a second soil test should be taken six to nine months after application and before planting.

At planting, a transplant starter solution can be applied to each plant. Most any type of starter fertilizer appropriate for vegetables is suitable. Within three to five days after planting, a complete fertilizer low in nitrogen (N) as 10-10-10 (N, P, K) should be broadcast over the row at 20 pounds actual N (200 pounds 10-10-10) per acre. After 30 days, an additional 20 pounds of N can be applied if heavy rains have occurred or if straw mulch or sawdust has been applied. Reduce the second N application to 10 pounds if injected through an irrigation system. Do not apply dry fertilizer after July 1 or injected N after July 15. Avoid excess N getting close to young roots and damaging the plants.

Submit a leaf sample in early August to monitor plant elemental content. Specific element recommendations for brambles from leaves can be found in the Midwest Small Fruit Pest Management Handbook, Bulletin 861.

Nitrogen After Planting

During the second year, broadcast 30 pounds N in mid-April and broadcast another 20 pounds N in early to mid-June. Reduce the second application to 10 pounds if there is excessive growth or if N is applied through irrigation. Sources of N can be ammonium nitrate, urea, calcium nitrate, or potassium nitrate, either as dry fertilizer or for use in irrigation systems. Slow-release fertilizer can be used as a single application but do not apply after May 15.

In the third and subsequent years, the amount of the N applied per year can be based on the percent of soil organic matter (SOM) as shown in Table 5.

The first option is to consider a single or split application of N. For summer-bearing red, black, or purple raspberry and blackberry, the amount of actual N application in mid-April varies between 40 and 60 pounds per acre, depending on the percent of soil organic matter. This amount may be reduced if canes are vigorous or if irrigation during the summer months is used. For brambles, which ripen in late July to early October (fall primocane types), higher amounts of N are required. A split application is highly recommended for fall primocane raspberries.

Figure 9. Black raspberry near first harvest.

To get maximum yields, the plant needs to grow as rapidly as possible in early spring, thus the need for "high" rates of N before and as growth begins. If a complete fertilizer like 10-10-10 is used, it will require 400 to 800 pounds per acre, broadcast. It would be much more economical to use ammonia nitrate, calcium nitrate, or potassium nitrate and monitor phosphorus and potassium needs through soil and leaf analysis. The recommended amount of fertilizer should be reduced by 50 percent if it is banded and/or if the organic matter is high and irrigation is used on a regular basis (Table 6).

If microirrigation (trickle) is available, a water soluble nitrogen fertilizer can be applied through this system. This is the most efficient means of applying nitrogen to the crop. Contact your irrigation company field representative for help in calibrating the system to apply 30 to 50 pounds of actual nitrogen per acre per season (Table 6). A majority of the nitrogen should be applied between new shoot growth and harvest. Do not apply nitrogen after mid-August.

The need for large amounts of organic matter added to the soil for maximum bramble production cannot be stressed enough. However, as pointed out under site preparation, large amounts of organic matter will require additional nitrogen added to the crop. This organic matter can be added to the crop as strawy manure. Nine to ten tons of manure can be added per acre each year. The manure should be applied in mid-winter so as to not stimulate late growth in the plants, which can cause winter damage. Spring or summer applications can cause leaf burn. Even though the manure will provide nitrogen to the crop, 30 to 40 pounds of nitrogen should still be broadcast in late March.