Blackberry in Zone 8A — Southeast

Blackberries are a true taste of summer here in the Southeast, and well worth growing in your own backyard. Imagine fresh blackberry cobbler made with berries you picked yourself, or adding them to your morning yogurt. Their versatility and flavor make them a must-have, and they thrive in our long summer.

Our hot and humid summers can present challenges, but with careful attention to timing and a few preventative measures, you can enjoy a bountiful blackberry harvest. Our 245-day growing season gives you plenty of time to get your plants established and producing.

Transplant your blackberry bushes outdoors from mid-March through mid-April. This gives them time to settle in before the full heat of summer hits. Whether you're using bare-root canes or potted plants, be sure to harden them off for about a week by gradually exposing them to outdoor conditions.

Space your plants 3-5 feet apart to allow for adequate growth and air circulation. Keep an eye on the weather during this period; late-season cold snaps are possible, so be prepared to cover your young plants if temperatures dip unexpectedly.

Blackberries need consistent moisture, especially when they are fruiting. While they are more drought-tolerant than raspberries once established, don't let them dry out completely. In the Southeast, our humid summers can be tricky, so it's important to find the right balance.

During the active growing season, especially when the berries are developing, aim to provide about 1-2 inches of water per week, either through rainfall or irrigation. Use the "finger test" – stick your finger about 2 inches deep into the soil near the base of the plant. If it feels dry, it's time to water.

Water at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our humid climate. Overhead watering is fine if it's timed early in the morning so the leaves can dry out before nightfall. Signs of underwatering include wilting leaves and dry, shriveled berries. Overwatering can lead to root rot, indicated by yellowing leaves and a generally unhealthy appearance.

Mulch heavily around your blackberry plants with pine straw or wood chips. This helps retain moisture in the soil, suppresses weeds, and keeps the soil temperature consistent, which is especially helpful during our long, hot summers.

Blackberries are vining plants that need a strong support system to thrive. A trellis is the best option for most varieties, providing the necessary structure for the canes to climb and spread. This also helps with air circulation, which is vital in our humid climate to prevent disease.

Install your trellis before or at the time of planting to avoid disturbing the roots later. Train the canes to grow along the trellis, tying them loosely with garden twine as needed. If you're just starting out, thornless varieties are easier to manage on a trellis!

Pruning is essential for maintaining healthy and productive blackberry plants. After harvest, remove the spent floricanes (the canes that produced fruit) at ground level. These canes will not produce again, and removing them improves air circulation and reduces disease pressure.

During the growing season, tip-prune new primocanes (the current year's growth) at around 4-5 feet to encourage branching and more fruit production. As the first frost approaches around mid-November, you don't need to do any major pruning, but make sure to remove any dead or diseased canes to prepare for winter.

Expect your first blackberry harvest from mid-May through early July, depending on the variety and the weather conditions. The berries are ready to pick when they are fully black, not dark red. A ripe blackberry should pull off the vine easily without squeezing. Look for a dull surface, as shiny berries are often not fully ripe.

Harvest regularly, every few days, to encourage continued production. Gently grasp the ripe berries and pull them away from the plant. Avoid bruising the berries, and store them in a cool, dry place after picking.

Even as the first frost approaches in mid-November, continue to harvest any remaining ripe berries. While the growing season is winding down, you can still enjoy the fruits of your labor until the very end.

Blackberries can face several challenges in the Southeast, but knowing what to look for can help you stay ahead of potential problems.

Spotted Wing Drosophila

• What it looks like: Tiny fruit flies lay eggs inside ripening berries, causing them to become soft and mushy. You might see small white larvae inside the fruit.
• What causes it: This pest thrives in our humid summers.
• How to fix/prevent it: Use traps to monitor for adult flies. Apply insecticides labeled for spotted wing drosophila if necessary, following all label instructions. Consistent harvesting also helps reduce their breeding grounds.

Cane Blight

• What it looks like: Dark brown or purplish lesions appear on the canes, often near wounds or pruning cuts. The affected canes may wilt and die back.
• What causes it: Fungal disease that thrives in our humid conditions.
• How to fix/prevent it: Prune out infected canes and destroy them. Ensure good air circulation by spacing plants properly and pruning to open up the canopy. Avoid overhead watering.

Orange Rust

• What it looks like: Bright orange pustules appear on the undersides of leaves in spring. The leaves may become distorted, and the plant's growth is stunted.
• What causes it: Systemic fungal disease that is spread by spores.
• How to fix/prevent it: Remove and destroy infected plants. There is no cure for orange rust, so prevention is key. Choose disease-resistant varieties.

Japanese Beetles

• What it looks like: Metallic green beetles that skeletonize leaves and damage fruit.
• What causes it: These pests are common in the Southeast and are attracted to many plants, including blackberries.
• How to fix/prevent it: Handpick beetles off plants and drop them into a bucket of soapy water. Use insecticidal soap or neem oil for heavier infestations.

Southeast Specific Challenges Our hot, humid summers create ideal conditions for fungal diseases and pests like Japanese beetles and spotted wing drosophila. Be vigilant in monitoring your plants and take proactive steps to prevent problems before they start. Good air circulation, proper watering practices, and prompt removal of infected plant material are essential for growing healthy blackberries in the Southeast.

Companion planting can help your blackberries thrive here in the Southeast.

Tansy is a great companion plant because it repels many common pests, including Japanese beetles. Garlic can deter pests and also has antifungal properties, which is beneficial in our humid climate. Green beans fix nitrogen in the soil, which can help feed your blackberry plants. Mint is known to deter deer, which can be a problem for blackberry growers in some areas.

Avoid planting tomatoes, peppers, and potatoes near your blackberries. These plants are susceptible to diseases like verticillium wilt, which can spread to your blackberries. Also, they compete for the same nutrients in the soil.