Blackberry in Zone 5A — Great Plains

Blackberries offer a taste of summer that's hard to beat, and they're surprisingly rewarding to grow here in the Plains. Imagine homemade pies, jams, and fresh snacking right from your backyard. Plus, the vigorous growth of blackberries can create a beautiful and productive privacy screen.

We know the Great Plains throws its share of extreme weather at us, from sudden temperature swings to hail and variable rainfall. But with the right timing and a little planning, you can definitely enjoy a bountiful blackberry harvest within our 168-day growing season.

Transplant your blackberry plants outdoors from late April through late May, once the risk of a hard freeze has passed. Remember to harden off your bare-root or potted blackberry plants for about a week before planting. Gradually expose them to the outdoor elements, increasing the time each day.

Space your blackberry plants 3-5 feet apart to allow for good air circulation and plenty of room for growth. Keep an eye on the forecast during this time. We often get late-season cold snaps or even a hail storm, so be ready to protect your young plants if needed.

Blackberries need consistent moisture, especially while they're fruiting. Don't let them dry out completely, but avoid soggy soil. While they're more drought-tolerant than raspberries once established, consistent watering is key, especially with our variable rainfall here on the Plains.

A good rule of thumb is to water deeply once or twice a week, providing about 1-2 inches of water each time. Stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water. Watering at the base of the plant is best, especially with our low-to-moderate humidity, to avoid fungal diseases.

Signs of underwatering include wilting leaves and dry, brittle canes. Overwatering can lead to yellowing leaves and root rot. Mulch heavily around your blackberry plants to help retain moisture and suppress weeds. Straw, wood chips, or even grass clippings work well here.

Blackberry vines are vigorous growers and need sturdy support. A trellis system is the best option to keep your plants organized, productive, and off the ground. Install the trellis before or at the same time you plant your blackberries to avoid disturbing the roots later.

A simple wire trellis with posts every 8-10 feet works well. Train the canes to grow along the wires, tying them loosely with twine or plant tape. Consider the wind when positioning your trellis. A location that offers some protection from the strongest gusts will help prevent damage to the canes and fruit. 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 won't produce again.

In late spring or early summer, tip-prune the new primocanes (first-year canes) at about 4-5 feet tall. This encourages branching, which leads to more fruit production the following year. As the first frost approaches in early October, you don't need to do any major pruning, just make sure your plants are well-watered going into winter.

You can expect your first blackberry harvest from late June through mid August, depending on the variety and the weather conditions. The berries are ready to pick when they are fully black, not dark red. They should pull off the stem easily without squeezing.

A dull surface, rather than a shiny one, is another sign of full ripeness. Harvest every few days to encourage continued production. Blackberries don't ripen off the vine, so only pick the ones that are truly ready.

As the first frost approaches in early October, harvest any remaining ripe berries. If you have a lot of unripe berries, you can try covering the plants with a frost blanket to extend the harvest a bit longer, but don't expect them to ripen much further once the temperatures drop significantly.

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

Spotted Wing Drosophila *What it looks like:* Tiny, vinegar-like flies that lay eggs in ripening fruit. You'll see small, sunken spots on the berries, and the larvae will be inside. *What causes it:* These pests thrive in humid conditions, but even our low-to-moderate humidity can be enough for them. *How to fix/prevent it:* Use traps baited with vinegar or commercial lures. Netting can also exclude the flies. Remove any overripe or damaged fruit promptly.

Cane Blight *What it looks like:* Dark brown or purple lesions on the canes, often near pruning cuts. The canes may wilt and die back. *What causes it:* A fungal disease that enters through wounds in the canes. Hail damage can make this worse. *How to fix/prevent it:* Prune out infected canes below the lesion, disinfecting your pruners between cuts. Ensure good air circulation and avoid overhead watering.

Orange Rust *What it looks like:* Bright orange pustules on the undersides of the leaves in spring. Infected canes may be stunted and unproductive. *What causes it:* A systemic fungal disease. *How to fix/prevent it:* Remove and destroy infected plants. This disease is difficult to control once it's established. Choose rust-resistant varieties.

Japanese Beetles *What it looks like:* Metallic green beetles that skeletonize leaves and damage fruit. *What causes it:* These pests are attracted to stressed plants. *How to fix/prevent it:* Handpick beetles and drop them into soapy water. Use row covers to protect plants. Insecticidal soap can also be effective.

Great Plains Specific Challenges: The hot summers can stress blackberry plants, making them more susceptible to pests and diseases. Variable rainfall can make it difficult to maintain consistent moisture levels. Wind protection is essential to prevent cane breakage and fruit damage.

Companion planting can help your blackberries thrive in the Great Plains. Tansy repels Japanese beetles. Garlic deters various pests and fungal diseases. Green beans fix nitrogen in the soil, benefiting the blackberries. Mint can help deter pests, but be careful—it can be invasive.

Avoid planting blackberries near tomatoes, peppers, and potatoes. These plants are susceptible to verticillium wilt, a soilborne disease that can also affect blackberries.