Thornless Blackberry

A thornless blackberry cultivar that makes harvesting and pruning much more pleasant while producing equally large, sweet berries. Semi-erect canes benefit from trellising and can grow up to fifteen feet if left unpruned. Thornless varieties are generally slightly less cold-hardy than thorny types, so mulch the crowns well in northern gardens.

Thornless blackberries are propagated from root cuttings or tip-layering to maintain the thornless characteristic, as seed propagation may produce thorny offspring. For root cuttings, dig pencil-thick root pieces four to six inches long in late winter and lay horizontally in moist potting mix; new shoots emerge in four to six weeks. Tip-layering involves burying the arching cane tip two to three inches deep in late summer; roots form within six weeks and the new plant can be severed in spring. Softwood cuttings taken in early summer can be rooted under mist with rooting hormone.

The Season Plate

Your Thornless Blackberry Year

Composed for Zone 7 · typical seasons · frost passes Apr 2, returns Nov 1

Sow Thornless Blackberry Mar – Apr, pick Jul – Aug. Set your climate below and every date on this plate re-times itself.

Sowing window

Mar – Apr

re-timed to your frost dates

Plant out

after Apr 2

once frost risk has passed

First picking

around Mar 15

≈ 365 days from sowing · 3–5 kg per plant

Composed for —ColdTemperateMildWarmUse my locationUsed once to set your season · only the zone is kept

Week-by-week Thornless Blackberry reminders watering, feeding and pruning, timed to your dates

In the app

Frost alerts for your garden a warning before a cold night costs you the crop

In the app

Succession sowing dates so the picking never gaps mid-season

In the app

Keep my dates — free for 7 daysWe nudge you as each window opens · cancel anytime

Thornless blackberries offer all the prolific fruiting of traditional blackberries without the painful thorns that make harvesting and pruning a chore. These semi-erect cultivars produce stiff, upright primocanes that arch over at the tips and benefit from trellising for an organized, productive planting. Install a double-wire trellis system with wires at three and five feet before planting, and space plants four to six feet apart along the row.

Plant bare-root or container-grown plants in early spring in full sun with fertile, well-drained soil. Thornless blackberries are floricane-fruiting, meaning they produce fruit on second-year wood. In the first year, train new primocanes along the lower trellis wire. The following summer, these canes will flower and fruit on lateral branches. After harvest, remove all spent floricanes at ground level and tie the new primocanes to the trellis for next year's crop.

Tip primocanes at about five feet tall in midsummer to encourage strong lateral branching, which increases the number of fruiting sites the following year. In late winter, shorten lateral branches to twelve to eighteen inches. Water deeply once per week and mulch with three to four inches of organic material. Thornless varieties are generally slightly less cold-hardy than thorny types, so in zones 5 and 6, mulch the crown and lower canes heavily before winter or lay canes on the ground and cover with straw for insulation.

Plant thyme, borage, and mint near thornless blackberry rows to attract pollinators and deter pest insects. Borage is particularly beneficial, attracting bees that improve fruit set and potentially enhancing berry flavor. Avoid planting near raspberries or wild brambles to prevent disease transmission between Rubus species. Comfrey planted nearby accumulates nutrients and produces excellent mulch material. Keep away from nightshades that harbor verticillium wilt in the soil.

The Society Table

Thyme belongs beside it. Raspberry doesn't.

Old growers' knowledge, checked against Thornless Blackberry's real companion table below — test any plant you're growing.

Grows well in the company of · 3

ThymeBorageMint

Keep apart · 1

Raspberry

Plant Thornless Blackberry with good neighboursThe planner flags conflicts before they're in the ground

Thornless blackberries thrive in fertile, well-drained soil with a pH of 6.0 to 7.0. Amend clay soil with compost and aged bark to improve drainage, as blackberries are susceptible to root rot in waterlogged conditions. Apply balanced fertilizer in early spring as buds begin to swell and side-dress with compost or aged manure in late spring. Avoid heavy nitrogen applications that promote excessive cane growth at the expense of fruit quality. Maintain a thick mulch of straw or wood chips to conserve moisture and suppress weeds around the shallow root zone.

Ideal Temperature

Hardiness Zone Compatibility

Harvest thornless blackberries when the berries have turned completely black and have a slightly dull rather than shiny appearance. Shiny black berries are not yet fully ripe and will be tart. Ripe berries should detach from the plant with a gentle pull, coming away with the core intact inside the fruit. The absence of thorns makes harvesting thornless varieties dramatically easier and faster than thorny types. Pick every three to four days during the three to four week harvest period in midsummer.

Storage & Preservation

Fresh blackberries keep in the refrigerator for three to five days when stored in a single layer. For freezing, spread unwashed berries on a baking sheet, freeze solid, and transfer to bags for up to twelve months. Blackberries make outstanding jam, cobbler, pie, and wine. Their high pectin content makes them reliable for setting jam without additional pectin. Dried blackberries are excellent in trail mix and granola. Blackberry syrup is a versatile kitchen staple for pancakes, cocktails, and drizzling over desserts.

Troubleshooting Common Problems

Reduced cold hardiness compared to thorny varieties is the primary limitation, particularly in zones 5 and the colder portions of zone 6. Protect crowns and lower canes with heavy mulch or lay canes down and cover before hard freezes. Orange rust is a devastating and incurable systemic disease; remove infected plants immediately to protect the rest of the planting. Double blossom, or rosette, causes abnormal, bushy flower clusters that produce no fruit and must be pruned out. Sunscald can damage berries in extremely hot climates.

Growing Tips

1. Plant thornless blackberries in full sun for maximum yield — they tolerate partial shade but fruit quantity and sweetness decrease noticeably with less than six hours of direct sunlight per day.
2. Install a sturdy trellis of at least two horizontal wires (at 90 cm and 150 cm) before planting; trying to retrofit support around established canes is frustrating and risks damaging new growth.
3. Keep primocanes and floricanes on opposite sides of the trellis wire — train current-year growth in one direction and fruiting canes in the other to improve air circulation and simplify pruning.
4. Water deeply but infrequently rather than shallowly and often; encouraging deep root growth makes plants far more drought-resilient during summer heat spells.
5. Spread a 10 cm layer of wood chip or straw mulch around the base each spring to conserve moisture, suppress weeds, and gradually improve soil structure as it breaks down.
6. Avoid high-nitrogen fertilisers after midsummer — excess nitrogen promotes lush leafy growth at the expense of fruit bud formation and can make canes more susceptible to frost damage.
7. Renew the planting every eight to ten years by taking tip-layering cuttings from healthy young canes in late summer; this restores vigour and maintains the disease-free status of your stock.
8. In regions with late spring frosts, delay moving the mulch back from the crown until the frost risk has truly passed — a thick mulch layer can protect crowns down to -20°C.
9. Thin out the number of primocanes to four to six of the strongest per plant; overcrowded canes compete for light and nutrients, leading to smaller berries and increased disease pressure.
10. Harvest in the cool of the morning when berries are firm and their sugar content is highest; heat-softened berries picked in the afternoon deteriorate more quickly and bruise more easily.