Few summer treats can compare to a bowl of sweet fresh-picked raspberries or blackberries. Borne on the brambly stems (or “canes”) of shrubs in the genus Rubus, these toothsome morsels are about as delectable as hardy fruits get. And thanks to the efforts of modern breeders, growing raspberries and blackberries is easier than ever. There’s a brambly berry for just about every culinary garden!
What are Brambles?
Botanically speaking, each raspberry or blackberry is in fact a cluster (or “aggregate”) of fused, fleshy seed capsules, individually known as drupelets. The drupelets develop on the domed centers of the white, often inconspicuous, bee-pollinated flowers.
Bramble berries come in several colors including red, orange, yellow, purple, and black, with numerous hybrids between the variously colored types. Most brambles are hardy into colder regions of the United States (USDA Hardiness Zone 5 or so), but some are best suited for milder climes.
Fortunately, perhaps the hardiest of the lot are the red raspberries, widely regarded as the cream of the bramble crop. All derive from Rubus idaeus, a prickly, suckering shrub native to much of the temperate Northern Hemisphere. Hundreds of selections and hybrids of the species are in cultivation, each selected for the flavor, abundance, and timing of its fruits.
Standard forms of red raspberry flower and fruit on the growth of the previous year, ripening their fruits in early summer. So-called everbearing varieties go them one crop better by also producing blooms and berries in late summer on the current season’s growth (known as “primocanes”). Everbearing raspberries can be tip-pruned in early spring for two crops, or sheared close to the ground for a single large late-season harvest.
Growing Red Raspberries
Red raspberry plants thrive in sun and fertile humus-rich soil (amend or mulch lean or heavy soil with a good compost such as Fafard Premium Natural & Organic Compost). Plant the canes in widely spaced rows (10 feet or so apart), removing suckers that wander more than a couple feet from the rows’ centers.
Recommended summer-fruiting varieties include ‘Killarney’, ‘Nova’ (which fruits a bit later than ‘Killarney’), and ‘Encore’ (which ripens later still). Everbearing red raspberries include ’Autumn Bliss’ and ‘Heritage’ (the latter bearing its fall crop too late for areas with short growing seasons). Yellow-fruited cultivars of Rubus idaeus include ‘Anne’ and ‘Fallgold’ (both everbearing).
Growing Black Raspberries
The eastern U.S. native Rubus occidentalis – commonly known as black raspberry – has sired several cultivars that make excellent choices for cold-climate gardens. The aromatic, dome-shaped berries mature to purple-black in late spring or early summer, depending on the variety. Look for the large-fruited, midseason-bearing ‘Jewel’, and the relatively early-fruiting ‘Haut’.
Black raspberries have similar soil and sun requirements to those of their red kin. Plant them (as well as blackberries and purple raspberries) at 4-foot intervals in rows spaced 8 to 12 feet apart. Prune the tips of black raspberry (and blackberry) primocanes in spring as soon as they reach full height, and remove all second-year canes after they fruit.
Least hardy of the brambles are the group known as blackberries, a complex swarm of cultivars deriving from a hodgepodge of species. Their large, relatively elongated fruits ripen as the black raspberry season comes to a close. Relatively few blackberry cultivars are reliably hardy north of USDA Zone 6, and many hit their stride only in mild-winter areas such as the Southeast and Pacific Northwest. Among the best of the hardiest cultivars are ‘Darrow’ and ‘Illini Hardy’, which succeed into USDA Zone 5.
Gardeners in warmer districts can choose from a broad array of blackberries, including numerous thornless, semi-erect cultivars developed by the University of Arkansas and other breeding programs.
Crosses between red raspberries and black raspberries have yielded yet another tribe of brambles: purple raspberries. Intermediate in color, size, and hardiness between the two parent types, this group is best known by the cultivar ‘Brandywine’, whose large, flavorful, tart fruits come later than those of most other raspberries. Other notable cultivars include ‘Royalty’ and ‘Success’.
The various colors and seasons of bloom of modern raspberry and blackberry varieties offer a spectrum of delicious possibilities for bramble fanciers. Continuous spring-to fall harvest of berries is there for the growing, in a rainbow of colors. It’s a great time to be a bramblephile.