The wild red raspberry of the United States is widely distributed and its fruit, as found wild, often approaches closely in quality the European red species (Rubus idœus). As it seems to have naturally crossed with the black-cap species, and crosses readily with the European red varieties, it is singular that as yet no attempt has been made to improve this valuable species except by selection and cultivation, and we have no evidence of its crossing with other species, except naturally with the black caps. Yet it is quite possible from what we know of their history that such choice varieties as Cuthbert and Turner are hybrids, with the added quality and size of the European varieties.
The American red varieties and the sprouting purple canes are propagated by sprouts and root-cuttings. Nearly all the varieties sprout so freely that a resort to other methods is not needed. But the Philadelphia and some other sorts sprout more sparingly and are often grown from root-cuttings (50. Propagation by Root-cuttings). In some cases also propagators thrust a spade down in a circle around the plant about eight inches from the centre, which increases the sprouting very materially. Transplanting, in rows for fruiting the suckers of the reds and sprouting purple canes, can be done easily and rapidly, as they start from the cut-back top like a small shrub. Plant firmly at the depth they stood before taking up and cut back the tops to near the ground surface of the hills or stools. The first cultivation of spring may be with a small turning-plow, but all after culture should be with the cultivator, taking care to keep the general surface about level. The hoe must also be used between the stools.