Blackberry in Zone 6A — Great Plains

Blackberries offer a sweet-tart taste of summer that's hard to beat, especially when you've grown them yourself right here on the Plains. They're fantastic for jams, pies, or just popping straight into your mouth. Plus, blackberries are more forgiving than some other berries in our variable climate, making them a rewarding choice.

Our extreme weather can throw curveballs, from late frosts to summer heat waves and the occasional hail storm. But with careful timing and a little extra attention, you can absolutely enjoy a bountiful blackberry harvest within our 188-day growing season.

Transplant your blackberry plants outdoors from mid-April through mid-May, once the threat of hard frost has passed. Before planting, be sure to harden off your bare-root canes or potted plants by gradually exposing them to the outdoor elements for about a week. This helps them adjust to our intense Plains sunshine and temperature swings.

Space plants 3-5 feet apart to give them plenty of room to grow. Keep an eye on the weather forecast – a late cold snap or even a bout of hail can damage young plants, so be prepared to cover them if needed.

Blackberries need consistent moisture, especially when they're establishing and fruiting, but they aren't big fans of soggy roots. They are a little more drought-tolerant than raspberries once established, but don't let them completely dry out. During our hot Plains summers, check the soil moisture regularly.

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. Aim for about 1-2 inches of water per week, especially during fruiting. Water deeply at the base of the plant to avoid wetting the foliage, which can encourage fungal diseases in our low-to-moderate humidity.

Yellowing leaves can indicate overwatering, while dry, crispy leaves often signal underwatering. A good layer of mulch, like straw or wood chips, will help retain moisture and regulate soil temperature, which is essential with our temperature swings.

Blackberry vines are vigorous growers and need strong support to keep them off the ground and prevent them from sprawling. A sturdy trellis system works best. This could be as simple as running wires between posts, or a more elaborate T-trellis.

Install your trellis system before or at the time of planting to avoid disturbing the roots later. Train the canes to grow along the wires, spacing them evenly for good air circulation. Consider the wind when planning your trellis – orient it to minimize wind exposure, or use a windbreak to protect your plants from strong gusts common in the Plains. Thornless varieties are a little easier to train.

Pruning is important for maintaining healthy blackberry plants and maximizing fruit production. After harvest, remove the old floricanes (the canes that produced fruit) at ground level. These canes won't produce again, and removing them improves air circulation.

During the growing season, tip-prune the new primocanes (the new, vegetative canes) at about 4-5 feet tall. This encourages branching, which leads to more fruit the following year. Before our first frost around mid-October, remove any dead or diseased canes to prepare the plants for winter.

Your first blackberry harvest should arrive sometime between mid-June and early August, depending on the variety and the weather that year. Keep a close eye on your berries as they develop.

Ripe blackberries will be fully black, not dark red, and will pull easily from the vine without squeezing. A dull surface indicates full ripeness, rather than a shiny one. Harvest regularly, every few days, to encourage continued production.

As the first frost approaches in mid-October, harvest any remaining ripe or nearly ripe berries. While blackberries don't ripen off the vine, you can use the nearly ripe ones for jams or pies.

Here are some common problems you might encounter with blackberries in the Great Plains:

Spotted Wing Drosophila

• What it looks like: Tiny puncture marks on ripening fruit, with larvae inside the berries.
• What causes it: This fruit fly lays its eggs in ripening fruit. Warm, humid conditions can worsen infestations.
• How to fix/prevent it: Monitor traps, use netting to exclude the flies, and harvest frequently to remove ripe fruit. Insecticides can be used as a last resort.

Cane Blight

• What it looks like: Brown or purplish lesions on canes, often near wounds or pruning cuts.
• What causes it: A fungal disease that enters through injuries. Wet weather promotes its spread.
• How to fix/prevent it: Prune out infected canes, sterilize pruning tools, and ensure good air circulation. Avoid injuring canes during cultivation.

Orange Rust

• What it looks like: Bright orange pustules on the undersides of leaves. Infected canes may be stunted.
• What causes it: A systemic fungal disease that infects the entire plant.
• How to fix/prevent it: Remove and destroy infected plants. There is no cure. Choose resistant varieties when available.

Japanese Beetles

• What it looks like: Metallic green beetles feeding on leaves and fruit, causing skeletonization.
• What causes it: These beetles are attracted to many plants.
• How to fix/prevent it: Handpick beetles, use traps, or apply insecticides. Row covers can protect plants during peak beetle activity.

Great Plains Specific Challenges: Our extreme temperature swings and variable rainfall can stress blackberry plants, making them more susceptible to diseases and pests. Consistent watering and mulching are essential for maintaining plant health. The wind can also damage canes, so providing adequate support and wind protection is crucial.

Good companions for blackberries include:

• Tansy: Repels some insect pests.
• Garlic: Deters pests and has antifungal properties.
• Green Beans: Fix nitrogen in the soil, benefiting blackberry growth.
• Mint: Repels pests, but be careful – it can spread aggressively.

Avoid planting blackberries near:

• Tomatoes, Peppers, Potatoes (Nightshades): These can harbor diseases that affect blackberries.