Photo: Alina Zienowicz Ala z — CC BY-SA 3.0 · source
Survives zone 3 through 9
Harvest calendar
Best planted in early spring after your last frost, or in fall before the ground freezes, depending on your climate.
The 'blackcap' — readily told apart from other brambles by canes coated in a powdery, whitish-blue bloom and by fruit that ripens through white, then red, before finally turning black-purple. Flavor is rich and more intense than red raspberry, good fresh but especially prized for jams, syrups, and pies. Unusual among brambles for tolerating black walnut's juglone. The trade-off is disease susceptibility — it is markedly more vulnerable than red raspberry to both orange rust and verticillium wilt, so site it away from old bramble patches and recent nightshade-family beds.
- Hardiness
- Zone 3–9
- Habit
- Shrub
- Edible part
- Fruit
- Ripens
- Summer–autumn
- Mature size
- Arching shrub 1.5–3 m, the cane tips rooting where they touch
- Light
- Partial to full sun — FAILS TO SET FRUIT in too much shade
- Soil pH
- 6.0–7.0 (near-neutral)
- Environment
- Temperate
- Native range
- Native to eastern and central North America, from New Brunswick and Ontario south through the Appalachians to Georgia and west to Missouri and Wisconsin.
- Status
- Cultivated
- Years to fruit
- 2–4 yrs
- Growth speed
- Rapid — canes reach 3–6 ft in a season, arching over to touch the ground as they lengthen.
- Spacing
- 90 cm (35 in) apart — about 1.2 per m² (1.1 per 10 sq ft)
- Leaf shape
- Trifoliate (three-leaflet) compound leaves with toothed margins, 1–3 in long. Canes are green and glaucous (with a powdery bloom) when young, aging to brown, and carry scattered short, curved prickles.
- Root system
- Perennial crown and roots with biennial canes, as in other Rubus, but new plants arise mainly from cane tips rooting into the soil rather than from extensive root suckering.
- Fruit description
- A true raspberry — hemispherical, about 15 mm across, ripening from white through red to black-purple, and separating cleanly from the receptacle when picked to leave a hollow center. Flavor is rich and distinctly more intense/winey than red raspberry, described in older sources as having 'a rich acid flavour' in the best forms.
- Propagation
- Propagated primarily by tip layering — in July, arching cane tips root readily wherever they touch soil, and the rooted tip is severed and transplanted in autumn — since this species tip-layers far more readily than it suckers from the roots. Division of rooted crowns and suckers is also used; seedlings are variable and not used for named cultivars.
- Pollination
- Self-fertile
The edible parts listed above are a starting point, not a field guide. Identify a plant with certainty — ideally against a local authority — before eating any part of it, and read the full disclaimer. Spotted something wrong? Report it.
Growing guide
Fertilizing. Lighter feeding than red raspberry — Pacific Northwest nutrient-management guidance recommends only about 0.5 oz nitrogen per plant in the planting year, rising modestly in established plantings. Prefers moist, highly organic soil; fruit fails to develop properly on dry, sunny sites without supplemental water.
How it spreads. Spreads chiefly by tip-layering rather than root suckering — arching canes bow over and root wherever the tip reaches the ground, and this rooting habit, repeated year after year, can build dense, nearly impenetrable colonies. Underground root suckering also occurs but is less prominent than in red raspberry.
Growing tips. Fruits on floricanes (second-year canes) — commercial black raspberry breeding has struggled to introgress the primocane-fruiting trait from red raspberry, so almost all cultivars still crop only on year-old wood; prune out spent floricanes after harvest and tip primocanes in summer to encourage branching. Canes are conspicuously glaucous (covered in a whitish-blue waxy bloom) and armed with short, curved prickles. Wants full sun to partial shade in moist, humus-rich soil. Notably more disease-prone than red raspberry: black raspberry is susceptible to the systemic, incurable orange rust (Arthuriomyces peckianus) that red raspberry resists, and verticillium wilt is typically more severe in black than in red raspberries — for both reasons, keep new plantings well isolated from old bramble patches and from ground that has grown potatoes or tomatoes.
Companion planting. Unlike most other brambles, black raspberry is consistently documented as juglone-TOLERANT — one of the few fruiting plants that can be grown near a black walnut without trouble.
Grow journal
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