Common Disease Problems
Anthracnose: This fungus causes spots on the canes with purple margins that can spread and cover the stem. Spots may appear on young leaves that are yellow with purple margins, and may cause holes in the leaves. Canes and stems may die back. Burpee Recommends: Remove and destroy infected canes and any leaf debris.
Crown Gall: Rough, wart-like growths or galls appear on the crown at or just below the soil surface. These can also form on the stems or canes of blackberries. Plants can become stunted, subject to drought stress and wind damage. Large enough galls may cause girdling which results in plant death. Burpee Recommends: Examine the canes prior to planting for any indication of galls. Avoid injury of the plant. You can remove the gall if it is small enough by cutting around it into healthy wood allowing that area to dry out, cutting into healthy tissue as little as possible. If plant is severely infected, remove it.
Orange Rust: This fungus causes plants to become stunted and weak with poor fruit production. Shortly after new growth appears in spring new shoots are weak and spindly, leaves are pale green to yellow. In a few weeks lower leaf surfaces are covered in bright orange powdery spores. Affected leaves wither and die by early summer. The disease is systemic, and remains throughout the plant so just removing infected leaves will not improve the health of the plant. Burpee Recommends: Dig up and remove infected plants and destroy nearby wild brambles. Remove plants before the spores are discharged if possible.
Phytophthora Root Rot: This soil borne disease thrives in poorly drained soils and can live in the soil for years. Above ground symptoms include pale or reddish leaves, small leaves, defoliation, branch die back, stunting and death. Burpee Recommends: Remove infected plants.
Powdery Mildew occurs on the top of the leaves in humid weather conditions. The leaves appear to have a whitish or greyish surface and may curl. Burpee Recommends: Avoid powdery mildew by providing good air circulation for the plants by good spacing and pruning. Contact your Cooperative Extension Service for fungicide recommendations.
Common Pest and Cultural Problems
Aphids: Greenish, red, black or peach colored sucking insects can spread disease as they feed on the undersides of leaves. They leave a sticky residue on foliage that attracts ants. Burpee Recommends: Introduce or attract natural predators into your garden such as lady beetles and wasps who feed on aphids. You can also wash them off with a strong spray, or use an insecticidal soap.
Japanese Beetles: Burpee Recommends: Hand pick early in the morning into a bucket of soapy water.
Borers: Larvae are worms with whitish bodies with brown heads about 1 inch long. The adults are clear-winged moths with black and yellow bands on their bodies. The larvae tunnel in canes and cause lateral growth to wither and canes to die. Burpee Recommends: Prune and destroy infested canes.
Leafhoppers: These appear in varying shades of green, yellow and brown, are very active and slender and wedge shaped. They can leave foliage pale and curled and leave secretions on the plants and fruit. They can spread disease. Burpee Recommends: Try insecticidal soaps. Contact your Cooperative Extension Service for control assistance.
Spider Mites: These tiny spider-like pests are about the size of a grain of pepper. They may be red, black, brown or yellow. They suck on the plant juices removing chlorophyll and injecting toxins which cause white dots on the foliage. There is often webbing visible on the plant. They cause the foliage to turn yellow and become dry and stippled. They multiply quickly and thrive in dry conditions. Burpee Recommends: Spider mites may be controlled with a forceful spray every other day. Try hot pepper wax or insecticidal soap. Check with your Cooperative Extension Service for miticide recommendations.
Are there seedless blackberries? Sorry, not yet!
Do I need two different varieties to get fruit? No, blackberries are self-fruitful.
Will I get fruit the first year? Expect fruit two years after planting. If you choose a primocane variety you may get some fruit the first fall after planting in spring.
How many harvests a year will I get? One unless you are growing a primocane-bearing blackberry. Primocane types produce two crops.
How far from red raspberries should I plant my blackberries? Plant at least 100 feet apart to avoid disease issues.