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How to Grow Blackberries: The Complete Guide

Photo Credit
Pixabay
Botanical Name
Rubus fruticosus
Plant Type
Fruit
Sun Exposure
Full Sun
Soil pH
Acidic
Bloom Time
Summer
Flower Color
White
Hardiness Zone
4
5
6
7
8
9
10

Planting, Growing, and Harvesting Blackberries

Catherine Boeckmann
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Blackberries, like raspberries, are very easy to grow. Once this native berry is ripe, get ready for an abundant harvest, picking every couple of days! Here’s how to grow and harvest blackberries in your backyard.

Basically, there are three types of blackberries:

  1. Erect thorny blackberries
  2. Erect thornless blackberries
  3. Trailing thornless blackberries

Erect blackberries are bushes that support themselves, while the trailing blackberries have long canes that must be trellised for support.

All blackberries are perennials; the roots survive year after year. However, the top of the plant above the soil is what we call biennial. This means that the canes grow vegetatively for a year, bear fruit the next year, and then die. However, every year the plant sends up new canes to replace those that died! For a great fruit harvest and to avoid a messy plant, pruning is important. (Learn about proper pruning techniques below.)

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Planting

When to Plant Blackberries

  • Plant when the canes are dormant, preferably in early spring.
    • Planting may also be done in late fall, however, it should be delayed until early spring in very cold areas as low temperatures could kill some hybrid varieties.
  • Blackberries and their hybrids are all self-fertile, so multiple plants are not needed for fruit production.

Choosing and Preparing a Planting Site

  • Select a site that receives full sun for the best berry yields.
  • Soil needs to be fertile with good drainage. Add organic content to enrich your soil. (Learn more about soil amendments and preparing soil for planting.)
  • Make sure you plant your blackberries far away from wild blackberries, which may carry (plant) diseases that could weaken your own plants.

How to Plant Blackberries

  • For semi-erect cultivars, space plants 5 to 6 feet apart. Space erect cultivars 3 feet apart. Space trailing varieties 5 to 8 feet apart. Space rows about 8 feet apart.
  • Plant shallowly: about one inch deeper than they were grown in the nursery.

Growing

How to Care for Blackberries

  • Mulching is important throughout the season to conserve moisture and suffocate weeds. Keep a thick layer of mulch surrounding plants at all times.
  • Blackberries require plenty of moisture, especially when growing and ripening. Ensure plants receive one inch of water per week and more in hot temperatures.
  • Blackberries benefit from fertilizing in early spring with an all-purpose fertilizer such as 10-10-10, or a 16-16-8. 

Trellis Trailing Blackberries

As mentioned above, trailing blackberries need a trellis or support. Explore a two-wire system, running a top wire at five to six feet with a second line 18 inches below the top wire. After the first year, there will be fruiting floricanes along the wires. Train the new primocanes into a narrow row below the fruiting canes. Directing all canes in one direction may make it simpler.

Pruning

We have provided detailed pruning information below, but do not be scared. The main idea is to simply remove the old canes that already bore fruit and let new ones take their place. 

  • Trailing blackberries: After the fruit harvest period, the old fruiting (floricanes) are removed to the ground. However, unless there is a lot of disease, it’s best to delay removing the old fruiting canes until they have died back considerably. This allows the dying canes to move nutrients back into the crown and roots. After you remove the old fruiting canes, you may train the primocanes up on the wires. Work with one or two canes at a time in a spiral around the trellis wires. Canes from adjacent plants may overlap a little. No pruning of primocanes is necessary.

In areas with low winter temperatures, it’s fine to leave the primocanes on the ground for the winter, where they could be mulched for winter protection. In the spring, after the danger of extreme cold has passed, train the old primocanes (now considered floricanes) up on the wires. Avoid working with the canes in cold weather, as they are more prone to breaking.

  • Erect blackberries produce stiff, shorter canes that come from the crown and from root suckering (often forming a hedgerow).

    Erect blackberries benefit from summer pruning. Remove the top one to two inches of new primocanes when they are four feet tall. This causes the canes to branch, increasing next year’s yields. Plants will require several pruning sessions to tip each cane as it reaches the four-foot height. Primocanes (suckers) that grow outside the hedgerow should be regularly removed.

    In the winter, remove the dead floricanes (old fruiting canes) from the hedgerow. Also, shorten the lateral branches to about 1½ to 2½ feet.

  • If you have primocane-fruiting erect blackberries, which are harvested in late summer/early autumn, cut all canes to the ground in the late winter (after the fall crop). In the summer, when the primocanes are 3½ feet tall, remove the top 6 inches. The primocanes will branch, thereby producing larger yields in the fall.

  • If you have semi-erect blackberries, they are easier to manage on a Double T Trellis. Install four-foot cross arms at the top of a six-foot post. Install a three-foot cross arm about two feet below the top line. String high-tensile wire down the rows, connecting to the cross arms.

    Semi-erect berries need to be pruned in the summer. When the primocanes are five feet tall, remove the top two inches to encourage branching. Several pruning sessions will be required as canes reach the appropriate height. In the winter, remove the dead floricanes (old fruiting canes). Spread the primocanes (new floricanes) out along the trellis. Canes do not need to be shortened. However, they can be if they are difficult to train.

Types

Here are some favorite blackberry varieties to investigate, but be sure to ask about varieties that fit your growing zone.

  • Erect Thornless: ‘Navaho,’ ‘Arapaho’  
  • Erect Thorny: ‘Cherokee,’ ‘Brazos,’ ‘Shawnee,’ and ‘Cheyenne’
  • Semi-erect Thornless: ‘Black Satin’
  • Trailing: Olallie

Harvesting

How to Harvest Blackberries

  • Pick only berries that are fully black. Mature berries are plump yet firm, a deep black color, and pull freely from the plant without a yank. Berries do not ripen after being picked.
  • Once blackberries start to ripen, they must be picked often—every couple of days. 
  • When picking, keep the central plug within the fruit (unlike raspberries).
  • Harvest during the cooler parts of the day. Once picked, place berries in the shade and refrigerate as soon as possible.

How to Store Blackberries

  • Blackberries are highly perishable and will only last a few days once harvested, even with refrigeration. 
  • Although fresh fruit is always best, blackberries can be stored by canning, preserving, or freezing. Techniques used for freezing blueberries can also be used on blackberries.
Gardening Products

Pests/Diseases

  • Raspberry Borers
  • Fruit Worms
  • Gray Mold
  • Viruses
    • If your plant is suffering from the blackberry disease known as Raspberry Bushy Dwarf virus, the leaves will have some bright yellow on them, and the leaves of the fruiting vines may have a bleached look in the summer. The disease known as Blackberry Calico will cause faint yellow blotches on the leaves of the plant.

Wit and Wisdom

Blackberries, raspberries, and strawberries are very high in ellagic acid, which is an antioxidant that acts as a scavenger, helping to make potential cancer-causing chemicals inactive. Ellagic acid reduces the genetic damage caused by carcinogens like tobacco smoke and air pollution. Blackberries also contain other antioxidants that can help lower cholesterol and ward off cardiovascular disease.

Recipes

Blackberry Cobbler
Blackberry Soup
Refrigerator or Freezer Blackberry Jam
Fruit
About The Author

Catherine Boeckmann

Catherine Boeckmann loves nature, stargazing, and gardening so it’s not surprising that she and The Old Farmer’s Almanac found each other. She leads digital content for the Almanac website, and is also a certified master gardener in the state of Indiana. Read More from Catherine Boeckmann
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Comments

Mariana (not verified)

9 months 2 weeks ago

Hi - I'm looking for guidance on transplanting mature blackberry bushes. I'm in Zone 10a, so no frost/freeze. I've read elsewhere that the best time is when they are dormant; and that I should dig up the root bulb with soil about 1 ft around and 1 ft deep, then replant with the crown at the same level as it was before. Anything else I should pay attention to? Thanks in advance.

WIldWoodGardener (not verified)

11 months ago

We had a large blackberry plant "appear" last year (I think it came from neighbor's, spreading under the fence). I let it go, and we got over a gallon of berries! Not much fruit this year. It is about 12 feet from my raspberries currently. I have heard that this may not be good, as diseases may propagate between the species. Should I remove it?

Yes, plant blackberries and raspberries in different locations to avoid the risk of different viruses. Also, keep red raspberry plants away from other raspberry varieties (black and purple). Removing any wild brambles in the vicinity is also a good idea since older brambles are more likely to carry the disease.

David Sampson (not verified)

11 months 3 weeks ago

I have thornless blackberries but they are sour is there anything to add to the soil to sweeten them i wait until they are completely ripe

Hi David,

Anything you added to the soil would not increase the sweetness of your berries. If harvested too early, blackberries will be sour. Even once they have turned black, you should wait to pick them until the shine has gone away and the berries are dull. The sugar levels increase as the berry becomes a dull color.

Hope this helps!

Ryan (not verified)

2 years ago

I believe this comment is incorrect:

"If you have primocane-fruiting erect blackberries, cut all canes off just above the ground in the late winter for the best fruit."

I have the Prime Ark Freedom. According to various online sources, canes should be pruned to the ground after the second fruiting year.

In terms of the  modern blackberries that fruit on primocanes, you could do it either way. 😄  The floricane crop will be harvested in late spring/early summer, whereas the primocane crop is harvested in late summer/early autumn. Double cropping does not reduce the yield of primocanes, and if you cut down the canes after the primocane crop, the next year you’ll get a bigger primocane crop. So, for those primocane fruiting varieties, you could grow them either way and still have berries.

Donna Harper (not verified)

2 years 1 month ago

I have a crop of blackberries that have some light brown spots on some of the berries. They taste okay but are they diseased?
The plants are 1-3 years old. This is the first time we have had this problem.

Jake Blacketer (not verified)

2 years 1 month ago

We've noticed the same thing on our fruit. It turned out to be the leftover bloom that turned brownish and kind of stuck to some of the fruit. We run our berries through a juicer after rinsing to make seedless jam and cordials. The old blooms don't seem to hurt anything.