Blackberries are characterized by their coloring, their unique composition and their flavor. Like raspberries, Blackberries are not technically a berry, but rather an aggregate fruit of individual drupes held together by very fine, nearly invisible hairs. Blackberries do not have a hollow center, instead they have a solid, edible core. When ripe, Blackberries have a deep inky sheen with purple highlights. They are succulent, soft, and juicy. Their flavor is sweet, slightly tart, with earthy undertones.
Blackberries are a bramble fruit within the Rosaceae family. A member of the Rubus genus, there are hundreds of specific varieties of Blackberries. The name Blackberry is often used as a generic term that refers to a wide range of bush berries that are considered Blackberries. These include loganberries, boysenberries, marionberries and ollalieberries.
Blackberries are a good source of vitamins A and C, iron, calcium and dietary fiber. Blackberries get their dark purple pigmentation from the phytonutrient anthocyanin, which also has antioxidant properties.
The sweet-tart flavor and earthy quality of Blackberries allows them to be used in both sweet and savory applications. The moderately high acidity of Blackberries cuts through the rich flavors of creamy and aged cheeses, or rich fatty meats. Blackberries can be added to ice creams, jams and baked goods. Blackberries also pair well with nuts, aged balsamic vinegar, salad greens, figs, and leafy herbs.
In a 2006 study published in The American Journal of Clinical Nutrition, scientists have indicated that the antioxidant content of Blackberries was far greater than that of other foods, making them one of the top cancer fighting foods.
Blackberries have a complex lineage, with native species on several continents, including Asia, Europe, North and South America. Native to the Pacific Northwest, In Europe, there are six species that are referred to as the aggregate species Rubus fruticosus.
Basically, there are three types of blackberries: 1. erect thorny blackberries, 2. erect thornless blackberries, 3. trailing thornless blackberries. The erect blackberries are bushes that support themselves. The trailing blackberries have long canes that must be trellised for support.
All blackberries are perennials; the roots come back 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.
- Blackberries and hybrids are all self-fertile, so multiple plants are not needed for fruit production.
- Select a site that receives full sun for the best berry yields.
- Soil needs to be fertile with good drainage. Add organic content to enrichen your soil. (Learn more about soil amendments and preparing soil for planting.)
- Make sure you plant your blackberries far away from wild blackberries that may carry viruses.
- 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.
- Planting may be done in late fall, however, it should be delayed until early spring in very cold areas as low temperatures could kill some hybrids.
- 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.
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 old fruiting canes are removed, 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, leave the primocanes on the ground for the winter where they could be mulched for winter protection. In the spring, after 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, cut all canes off just above the ground in the late winter for the best fruit. In the summer, when the primocanes are 3½ feet tall, removed 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.
- Raspberry Borers
- Fruit Worms
- Gray Mold
- If your plant is suffering from the blackberry disease known as Raspberry Bushy Dwarf virus, the leaves will be 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.
- 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 no 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
- 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.