Blackberries

Blackberries are a real treat and great for jams and desserts. The plants are very similar to raspberries, and grown the same way. Plants consist of thorny canes that grow perennially and bear fruit over the summer. Blackberries are either trailing, semi-trailing, or erect and require different spacing depending on the variety. Some people trellis trailing or semi-trailing varieties, but it isn’t always necessary. Allow fruit to fully ripen before harvesting.

Blackberries are self-fertile meaning the pollen of one cultivar can pollinate flowers of the same cultivar. Flowers must be pollinated to produce fruit, which about 90-95% of pollination is done by bees. Plant far away from wild blackberries which may carry viruses.

Light

Prefer full sun. Will grow in some shade, but produce less fruit.

Soil

Prefers fertile, well-draining soil, such as sandy loam. Use compost to amend soil.

Planting

Dig a hole wider than the root ball, but at the same depth as the container it is in. Best to plant in a narrow hedgerow. For spacing, plant semi-erect cultivars 5-6 ft apart, erect cultivars 3 ft apart, and trailing varieties 5-8 ft apart.

Mulch

Provide 2-4 inches of mulch to cool the soil, conserve moisture, and prevent weeds.

Fertilizer

Fertilize with a balanced 10-10-10 fertilizer, such as Espoma Garden Food, according to directions.

Water

Water well after planting and supplement water as necessary to keep soil moderately moist, but not too wet.

Grooming

Weeding throughout the summer helps increase yields.

Problems

Blackberries generally have minimal pest and disease issues.

Japanese beetles can cause damage to the leaves. Refer to the article on Japanese Beetles for more information and treatment.

A recent pest of concern is the Spotted Wing Drosophila, which has been spreading across Wisconsin since 2010. It is an invasive species of fruit fly that lays eggs in ripening fruit that develop into tiny white larvae. Fruit tends to rot quickly and white larvae can be seen inside the fruit tissue. Be on the lookout for developing larvae, and if you suspect it’s presence you can submit a sample to the UW-Madison Insect Diagnostic Lab by following directions here. More information and ways to monitor can be found on the UW Extension website.

Blackberries at America's Best Flowers
Variety
Characteristics
Triple CrownSemi-trailing, thornless canes produce extra large berries with great flavor. Low-maintenance plants produce berries for about 5 weeks.