Training and pruning raspberries
The young canes grow from adventitious buds; without training or pruning the plant would quickly form an impenetrable thicket of stems. Because the root system is very wide-spreading, new canes may appear some distance from the parent plant.
The first summer after planting, cut out the old canes entirely when the young canes reach 25 cm (10”) high. The following late winter, tip prune all the canes slightly. Strong growing ones should be cut back to a good bud about 15 cm (6”) above the top wire; less strong growing canes should have the top 7.5-10 cm (3-4”) removed. This winter tipping, which should be done annually, will get rid of any diseased and damaged cane tips, and it will also encourage the canes to send out more fruiting laterals, thus increasing crop yields.
Healthy raspberry stools will normally produce more canes than are practical for good cultivation, so from the second summer onwards, allow only six fruiting canes per stool, choosing the strongest. If you remove all the weak, damaged or diseased canes early in the season, the selected fruiting canes will have more room to grow and more sunlight. Tie these six to the wires to keep them separated and firm. While these are flowering and fruiting, new shoots will appear and, as before, the obvious weak ones are cut out, and the best of the remainder left as replacements, to bear the following year’s fruit.
After cropping, cut to the ground the old fruiting canes; it is a good idea to remove and burn them immediately, to lessen the possibility of disease. Then tie in the selected young canes which have grown during the spring and summer for next year.
Autumn-fruiting varieties are pruned by cutting the old canes down to ground level in late winter or early spring; the plant will then produce canes in spring and summer on which fruit will be produced in autumn.
Care and cultivation
If dry weather occurs when the plants are flowering, watering is essential. Otherwise the new canes, which are growing at the same time, will be small and sparse, and next year’s crop will be poor. An annual mulch of well-rottedor manure in mid-spring will help conserve moisture. If the soil is dry, water it thoroughly before mulching. Because the roots are shallow and wide-spreading, the mulch should be spread 1 m (1 yd) on either side of the row. A good rule of thumb is to apply 2.5 kg (5 lb) of mulch per sq m (sq yd).
Weeds, which compete with the canes for moisture and nutrients, must be controlled. Over-vigorous hoeing can do more harm than good, though, because the shallow roots are very near the surface. Handis better. Remove unwanted suckers which may spring up between the rows, unless you want them for propagation, and cut back so they are not crushed by their own weight.
To the ground all small or spindly canes. Under good conditions, raspberries will not require extra fertilizer, but if cane production is inadequate, fertilizer should be applied in late winter. Scatter a nitrogenous one, such as sulphate of ammonia, at the rate of 30-45 g per sq m and one containing potassium, eg sulphate of potash, at 15-30 g per sq m.
The raspberry is a favourite target for birds, and netting is the only satisfactory long-term solution. For traditional raspberry rows, fix a T-piece to each end post so that the horizontal is about 1 m (3’) wide and above the canes. Stretch two wires between the cross pieces and drop the netting over to cover the canes; 2.5 cm (1”) nylon mesh is the best size netting.