Blackberry

Blackberry (Rubus allegheniensis) is the most productive bramble fruit per cane in most North American gardens. It spreads aggressively, tolerates poor soils better than raspberry, and produces more heavily on each cane. The main thing standing between most gardeners and a blackberry planting was always the thorns. Thornless cultivars solved that problem decades ago, and they now dominate the commercial market and home garden trade.

Cultivar types

Wild blackberries are thorny and sprawling. Modern cultivars divide into two growth habits.

Erect types produce stiff, self-supporting canes 5–7 feet tall. They still require some trellising for management, but won’t collapse under a fruit load. ‘Navaho,’ ‘Ouachita,’ and ‘Cherokee’ are thornless erect cultivars from the University of Arkansas breeding program - well-adapted to the mid-South and increasingly grown nationally.

Trailing (semi-erect) types produce long, arching canes that require a trellis. Higher yield per cane but more management. ‘Triple Crown’ is the most widely planted thornless trailing cultivar in the Eastern US; ‘Black Satin’ is a reliable option for Zones 5–9.

Like raspberries, blackberries produce on second-year canes (floricanes). The root system is perennial; individual canes are biennial. First-year primocanes grow and harden; second-year floricanes fruit and then die.

The ROI case

A blackberry planting produces more per cane than raspberry and is more drought-tolerant once established. Established plants yield 3–6 lb per cane cluster annually starting in year two (University of Arkansas Cooperative Extension Service, Commercial Blackberry Production, MP297, 2019). At $5–$8/lb retail (USDA AMS Market News, 2023), a 10-foot row at productive maturity returns $75–$150 in fresh fruit value per season.

The long-term economics are compelling because blackberry expands itself. Tip-layering - where arching canes touch the soil and root - creates new plants every season. You can dig those rooted tips and extend your planting, or simply let the row fill in. A $15 planting becomes a permanent fruiting system. The per-pound cost after year one is effectively zero beyond labor.

Growing requirements

Plant in full sun in well-drained soil. Blackberries tolerate moderately poor, rocky soil better than most fruit crops, but they don’t tolerate standing water. Phytophthora root rot is a real risk in saturated sites. If drainage is marginal, raise the planting bed 8–12 inches.

Soil pH 6.0–6.5 is optimal; blackberries tolerate a slightly wider range than blueberry or raspberry (Strik, OSU Extension, Growing Blackberries in Your Home Garden, EC 1303). Incorporate 2–3 inches of compost before planting.

Space erect types 3–4 feet apart in rows; trailing types 5–6 feet. Install a two-wire trellis at planting: wires at 3 feet and 5 feet, posts every 15–20 feet. Training canes to the trellis from the start makes management much simpler than trying to sort out a tangle after the fact.

After the first year, tip-prune primocanes to 3–4 feet for erect types. This forces lateral branches that increase fruit production. After harvest, cut all spent floricanes to the ground immediately and remove them from the site - leaving dead cane debris invites disease.

Water at 1–1.5 inches per week through the growing season. Drip irrigation is preferred. Mulch 3–4 inches deep to retain moisture and suppress weeds.

What goes wrong

Orange rust (Arthuriomyces peckianus and Gymnoconia nitens) is the most destructive blackberry disease. Infected plants develop pale green leaves in spring that turn bright orange-yellow on the undersides, covered in spore pustules. Orange rust is systemic - it persists in the root system permanently. There is no cure. Dig out and destroy infected plants immediately, roots and all. Do not compost them.

Rosette (double blossom) (Cercosporella rubi) causes abnormal flower development - blooms look doubled, frilly, and rosette-like. Infected flowers don’t set fruit. The pathogen spreads via cane lesions. Remove infected canes to ground level; avoid overhead irrigation.

Blackberry psyllid (Trioza tripunctata) is a sucking insect that causes witches’ broom on infected shoots - tight, bunched growth at cane tips. Infested shoot tips should be removed and destroyed.

Stink bugs (various Halyomorpha halys and native species) have become a significant pest of bramble fruit in the Mid-Atlantic and spreading westward. They feed on developing fruit, causing white internal damage called “cat-facing.” Row cover before fruit set is the most effective physical barrier; exclusion nets sized for berry protection are available commercially.

Harvest and storage

A ripe blackberry is fully black, slightly dull rather than glossy, and releases from the receptacle with gentle pressure. If it’s still glossy and firm, it needs another day or two. Unlike raspberry, the receptacle stays with the blackberry fruit when picked - the hollow center is not visible after harvest.

Blackberries are more durable than raspberries but still bruise at the bottom of a deep container. Use shallow containers for harvesting. Pick every two to three days at peak season. Refrigerate immediately and use within four to five days. Freeze the same way as raspberries: single layer on a sheet pan first, then bag.

Blackberry flavor concentrates well under heat - jams, cobblers, and sauces are where the flavor holds best.

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Related crops: Raspberry, Strawberry

Related reading: First Three Years ROI - how to track whether a perennial planting is paying off