These shrubs are among the hardiest of the bush fruits and are perfectly at home in the northern United States and southern Canada. The canes are biennial, as in they normally are produced one year, fruit the second year and then die and should be removed in the annual thorough pruning that these shrubs require to keep them in good bearing condition. The new shoots either appear at the base of the plant or as suckers a foot or so removed from the plant.
There are 2 types of red raspberries, those that only fruit once a year, and those sometimes termed “ever-bearing” that fruit early, in the season (July), have a few weeks rest, and then fruit again in Sept. After growing both types, I must admit to liking the “ever-bearing” group better, for in a good growing season it does seem that we have fresh fruit from early summer to frost, with a break of about 2 two weeks. However, some gardeners may not care for raspberries this much or may be away from home in early summer. It also must be admitted that fruits of the “ever-bearing” types may not be quite as large or sweet as the others. So, one has a decision to make concerning the type to plant.
No work is required except seeing to it that all canes are kept within the limits set by the wires. There are other methods, but this works well and, if made of sturdy materials, needs no attention for years.
As noted, pruning is done after fruiting in the late summer, for the crop varieties, or in the fall, winter or early spring for the crop or “ever-bearing” varieties. Canes left may have the tops snipped off at about 41-106 ft. high, depending on variety.
The Black Raspberry (or Blackcap) and the Purple Raspberry are treated in the same manner, except that the shoots tend to be long and trailing and the ends might well be cut off when they have reached their proper manageable height (5-6 ft) which forces lateral growth, especially desirable since these plants only produce 3-12 canes per plant and can get too heavy if the canes are cut off much higher. This heading back should be done as soon as the growth reaches this height.
Propagation is simply by dividing the plants, digging up rooted suckers, or using a sharp spade through the center of a plant from which many canes have developed. The black-caps are reproduced by tip layering, merely selecting a long arching shoot, placing the tip firmly in the ground with just the end showing. This is done in late summer and by the following spring this should be rooted.
Planting can be done in either the fall or the spring, but ether things being equal, early spring is probably best. When properly planted (about 30-45 in. apart in the row for the raspberries and 3-6 ft. apart for the blackcaps) the canes are cut back to about 5 in.