How to Grow Blackberries

Blackberries are often considered a bitter fruit, but many varieties bred for home gardens are sweet, slightly tart, and absolutely delicious.

Blackberries are one of the easiest fruits to grow, have few natural pest or disease problems, and the shrubs or vines quickly fill a garden bed within a few seasons. They’re delicious eaten fresh, or cooked into syrups, jams, or pies.

• Like raspberries, blackberries grow on canes, which are hard, woody stems.
• A blackberry fruit is actually made up of many fruits (called drupelets), each of which contains a seed.
• Blackberries are biennials, which means they grow canes in the first season but flowers and fruit in the second season. New canes are produced each year.
• A blackberry patch is for the long haul – roots and crowns can live anywhere from 15-40 years depending on conditions, so once you plant blackberries, you’ll have them for life.

Blackberries grow on Floricanes or Primocanes

Blackberries grow on woody “canes”, which are produced from the plant every year. Canes are the erect shoots that flower and fruit. But blackberries are biennials, which means a cane produces fruit in its second year. A first-year cane is called a Primocane which does not fruit on most varieties. In its second year, the Primocane, now called a Floricane, bears flowers and fruit and then dies. Most blackberry varieties are summer-bearing, known as Floricane-fruiting.

Some varieties of blackberries are fall-fruiting or everbearing, known as Primocane-fruiting. In these varieties, the tips of the Primocanes flower and fruit in the fall of their first year. The tips of the primocane that fruited die back in winter. The remaining cane overwinters and becomes a Floricane the following year. Floricanes die after fruiting with these plants as well.

There are 3 types of blackberries for home gardeners

The varieties are categorized by their growth habit: trailing, erect, and semi-erect.

Trailing Blackberries

Trailing blackberries produce primocanes that trail along the ground unless they’re supported by a trellis. Canes may grow more than 15 feet long if not pruned. Varieties in this category typically produce fruit the earliest of all types and the fruit has small seeds and excellent flavor. These are less winter hardy, may have thorns or be thornless, have excellent berries, and need trellising.

Erect Blackberries

Erect blackberries produce stiff, thorny upright canes each year from the crown and root buds, which means these plants easily spread throughout your garden. Erect varieties typically fruit midseason and the berries have a mild aroma and flavor, but larger seeds than trailing varieties. Canes need to be pruned back each year to encourage side branching which will produce more fruit. Erect varieties do not need to be trellised. These are generally more winter hardy and produce large, sweet berries.

Semi-erect blackberries

Semi-erect blackberries may be thornless or have thorns. They produce thick primocanes and bear fruit from late summer through fall with higher yields than erect varieties. The primocanes initially grow erect but then branch, and the side branches droop to the ground. When the tips come in contact with the ground, the plants form a new root from the tip and produce a new plant.

Choose a blackberry cultivar that is appropriate for your region, as those not adapted for your hardiness zone may not be winter hardy. This shouldn’t be a problem if you buy your plant at a reputable local nursery.

Where to plant blackberries

Choose a site that receives as much sun as possible, preferably 6-8 hours of direct sunlight daily. The more sunlight your blackberries get, the more they will fruit. Do not plant blackberries in an area subject to high winds, as cold winter winds can damage Primocanes on some varieties.

Soil considerations

Blackberries are pretty tolerant of most soils, but you must insure that the soil drains freely as blackberries hate “wet feet”. Add soil amendments like compost or peat moss that improve drainage if you live in an area with heavy clay soil. If your soil is very heavy clay, if the soil is polluted, or is problematic in some other way, plant blackberries in raised beds in order to control the quality of the soil.

Blackberries do best in a soil pH between 6.0 – 6.7. In soils with a pH higher than 7.0, your plants will have problems – a whitening of the leaves called chlorosis, and an overall decline in health, because the plant cannot absorb iron from the soil. After a pH test, modify the soil with sulfur (to acidify) or lime (to make it more alkaline).

Blackberries prefer a soil with a high percentage of organic matter, so add yard waste compost or composted manure every year in early spring and after fruiting in fall. Little to no fertilizer should be needed if your plants are regularly fed with compost.

Tips for planting blackberries

• If you live in an area with severe winters, growing blackberries may be a problem, as the canes of many species will be damaged or destroyed by the weather. Blackberries will not fruit above areas on the cane that are damaged. It’s always important to choose a variety that is hardy in your USDA zone.
• Your blackberry plant will either be bare root or in a container. Depending on the cultivar, planting is slightly different. Blackberries should be planted as early as possible in spring, as soon as the soil can be worked. Dig a hole slightly larger and deeper than the root ball. If your plant is in a container, remove all of the potting soil via root washing. Place the plant in the hole, spread its roots out, and backfill with the same soil that came out of the hole (assuming your soil isn’t terrible – see above). Set the plant so that the roots attached to the cane are 1 to 2 inches below the soil surface. Top off the soil with compost after planting in the area of the root zone.
• For most home gardeners, you’ll only need 1 plant, as it will quickly fill your garden bed with new Primocanes after a few years. But if you do have a very large area to grow in, and want a load of fruit fast, trailing plants should be spaced 5-8 feet apart, semi-erect varieties 5-6 feet apart, and erect varieties spaced 3 feet apart.

Trellising blackberries

Blackberries greatly benefit from trellising. This gets the canes up into the light, the fruit off the ground, and makes pruning and harvesting much easier. More light means more fruit. They can be grown without a trellis but after a few seasons your blackberry garden will be unruly and wild.

To make a homemade blackberry trellis:

• Use 6-foot metal stakes spaced 6 feet apart. (that’s 6 feet above ground so your canes can climb).
• String 12-14 gauge wire between each stake at about 5 feet off the ground and 18″ below the top wire.
• Mature blackberries are very large plants and they’ll need significant anchoring so make sure your trellis is sturdy and can hold up in high winds.
• Fruiting floricanes should be tied to the wires in spring and new primocanes trained into a narrow row below the floricanes.

Watering blackberries

Blackberries need 1-2″ of water a week in the absence of rainfall. This is especially important as fruits are developing. Blackberries have a shallow, fibrous root system that dries out quickly so consistently damp soil is important.

Fertilizing blackberries

In most soils, only spring and fall feedings of compost are necessary. Compost also helps suppress the weeds that compete with blackberries’ shallow root system. If your plants are struggling and you suspect that fertility is the problem, please perform a soil test before adding fertilizer.

How to prune blackberries

Pruning is the key to successful blackberry growing. The technique differs slightly whether your variety is a primocane-fruiting or floricane-fruiting variety.

Always prune fruiting floricanes to the ground when they have died. Do not prune new plants in the first year. At the beginning of summer, use your fingertips to tip back each developing, new primocane (new canes) to 48 inches. By tipping back the ends of the canes growth hormones are released, which stimulates new growth from the lateral buds along the cane. This increases the number of branching lateral canes where flowers and fruit are produced. Do not prune floricanes during the growing season unless they’ve grown too high for your trellis and make harvesting difficult. At the end of the growing season, prune out all floricanes with loppers and compost or discard all debris to avoid diseases and pests.

Pruning Floricane-fruiting blackberries

These blackberries benefit from winter pruning and summer pruning or “tipping”. During winter when the plant is dormant, prune out, down to the ground, every cane that produced fruit the previous season. As these are dead, they’re of no more use and only serve to harbor insects and possibly disease. Then, prune any excessively long canes to 2-3 feet. In the summer, prune the tops (tipping) of semi-erect varieties when they reach the top wire of your trellis. For erect varieties, tip the primocanes when they grow to 3 feet. This forces the canes to branch laterally and this is where fruit will be produced the following year.

Pruning Primocane-fruiting blackberries

Primocane fruiting varieties produce fruit on first-year canes late in the season. In early summer when canes reach about 3-feet, prune the tips. This encourages branching and increases bud formation. When the canes die in winter, prune them out of your patch.

Blackberry Pests

Blackberries aren’t plagued with too many pest problems, but of course, no plants are exempt. Various species of aphids, mites, japanese beetles, leafhoppers, nematodes, borers, spotted lantern flies, and drosophila can cause damage. Infections from fungi are also common. To avoid fungal infections, prune out all canes that fruited in the season and water the root zone, not the foliage if possible (blackberry foliage is rather robust to say the least). See this excellent resource from the University of California on Blackberry pests and diseases.

Resources: Oregon State University Extension, Growing Blackberries in Your Home Garden, Utah State University Extension, Blackberry Management in Utah, Iowa State University Extension, Growing Blackberries in the Home Garden.

We garden in Pennsylvania, United States, zone 6B. Much of the info we share is based on gardening in our temperate area. But many of the flowers, vegetables, and fruit we write about can be grown in soil other than ours (clay) and significantly different weather conditions and elevations. You might need to choose specific varieties for your region, modify your garden, add soil amendments, or adjust the soil pH to match our results. Please check your local university extension website for specifics for your area.