What Is a Raspberry's Growth Habit?

Canes

• Both red and yellow raspberry cultivars grow stiff canes with a more upright growth habit than the canes of either black or purple raspberries. The black or purple types produce slender canes which arc back toward the ground. All raspberries grow canes which live for two growing seasons. Primocanes, or first-year canes, of most varieties bear no fruit in the first season. Second-year canes, called floricanes, flower during their second spring and die back after bearing fruit. Two-wire trellises built to match the variety's height allow easy separation of first- and second-year canes. Floricanes lean against the supporting wires while primocanes grow vertically in the center of the row.

Spreading Habits

• Growth habits of the perennial root system also vary between the two major raspberry groups. Black and purple raspberries send up new canes from the root crown only. Red and yellow raspberries grow new canes from both root crown and the spreading roots themselves. Planting methods take advantage of both types of growth habits in order to increase fruit production. Planting black and purple varieties in widely spaced hills improves the crop by giving individual plants extra growing room and more nourishment. Red and yellow raspberries naturally fill in spaces between plants with more canes. Tilling the outer edges of the bed focuses nourishment on the plants in the bed's center.

Fruiting

• Individual raspberry varieties also display different fruiting habits, falling either into summer-bearing or everbearing categories. Red and yellow varieties provide most of the everbearing raspberry cultivars. Everbearing raspberries fruit twice and bear fruit at the tips of primocanes late in the first summer. Everbearing raspberry floricanes also produce a crop in fall of the second summer, on parts of the canes that didn't bloom the first year. Summer-bearing varieties produce one heavier crop in summer or fall of the second year. Varieties also fruit at different times, some types bearing in midsummer and others in late fall.

Propagation

• Growers who know the growth habits of particular raspberry varieties could expand raspberry beds from their own plants rather than buying more nursery stock. Red and yellow raspberries need control and thinning since the plants spread on their own. Thinning out weak canes places more of the plant's energy in strong canes and increases both fruit and plant vigor. Black and purple raspberries spread by a different method. The arching cane tips often root during the first winter, if buried and mulched. Once the plant shows independent growth the next spring, cutting the tip of the cane free allows transplanting to a new location.