How to Grow Blackberries

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.

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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.

Floricanes, Primocanes, and fruiting

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 to 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 blackberry gets, the more it 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 any local soil, 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.

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 fin 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). Add compost after planting in the area of the root zone. Set the plant so that the roots attached to the cane fall from 1 to 2 inches below the soil surface.

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.

Doug Hall