How to Grow Blackberries in Raised Beds: 9 Pro Tips

Blackberries are an incredible summer fruit, but some gardeners shy away from adding them to their landscape because of their aggressive nature. You can train them to be polite and grow within the lines, but it takes time and effort. If you want to grow blackberries but can’t commit to the hassle of their potential unruliness, grow them in raised beds.

Growing annual gardens in raised beds is a popular gardening trend that isn’t going away, so why not grow berries this way? This method keeps them from taking over your garden, and harvests will be much more enjoyable. Epic Gardening has a variety of raised metal and cedar wood beds to choose from to fit your garden design. Raised beds will help you control the soil fertility and ensure proper drainage. 

Let’s discuss nine pro tips for successfully growing blackberries in raised beds. 

Choose The Right Variety and Garden Spot 

Blackberry varieties differ in ease of maintenance, zone performance and hardiness, best uses, growth habits, and flavor. Choosing one that will do well in your growing region and produce the highest yields is essential.

Blackberry bushes perform best in full sun and require good soil drainage. If planted in the shade, yields will be drastically affected, and fruit may not properly ripen. 

Popular Varieties

‘Prime-Ark® Freedom’ Thornless Blackberry is internationally adored for its low-maintenance attitude, high yields, and giant, sweet berries. These berries are great for fresh eating or preserving to enjoy later. The plants are thornless and perform best in USDA zones 4 to 9. ‘Navaho’ is a heat-tolerant, erect variety for growers in zones 6a to 10b. Plants mature at four to five feet. 

‘Ilini Hardy’ is hardy in zone 5 and can grow to five feet. Create a lovely hedgerow by planting them along a fence line. ‘Jewel Black’ is a hybrid floricane variety often grown in the northeast for its hardiness and disease resistance. 

‘Baby Cakes®’ is a dwarf variety that grows three to four feet and produces large, sweet berries twice a year. Its compact growing habit and thornless canes make it perfect for container and raised bed growing. 

Trailing varieties have a creeping growing habit and are not recommended for container and raised bed gardening. Check with your local extension office if you’re unsure if a variety is right for your region.

Get The Timing Right 

Plant bare-root blackberry canes when dormant in early to late spring, a few weeks before the last anticipated frost. Soil in raised beds warms up sooner, allowing you to prepare your gardens sooner. 

Pro tip: If you receive bare-root plants and can’t plant them right away, keep the roots moist and store them in a dry, cool place until you can. 

Planting in the fall should only be done in growing regions that do not receive killing frosts, which could damage young plants. Protect them from cooler temperatures upon planting before winter. 

Irrigate

Consistent watering is critical as plants establish their root systems and acclimate to their new home. Water upon transplanting and daily for the first week. Ensure they receive an inch or two per week during the first season, and up to four inches is beneficial when plants are fruiting. 

Lay drip irrigation so you can deep water to avoid water evaporating off the surface and roots drying out. Continue watering until just before the first frost. Areas with consistent and ample rainfall may not need to water established plants. A moisture gauge will help you track the levels in your soil.  

Most blackberry varieties will thrive in fluctuating temperatures across regions. However, this fruiting bush requires proper water to produce fruits and remain healthy, so pay attention to this detail for good results. 

Feed

A great benefit of growing in raised beds is soil control. Berries have different soil needs from your average vegetable garden, so amend the soil before planting them. Blackberries prefer soil pH between 5.5 and 6.5. Use a soil test to determine your levels. Most growers will need to decrease pH levels before planting blackberries. Adding sulfur or using acidic fertilizers will do the trick. 

When preparing your plot, use amendments to adjust the nitrogen levels. Organic granular fertilizers meant to adjust nitrogen levels can take up to a month to be available for your plant’s use, so planning is critical. If you choose a liquid fertilizer, it’s available much quicker but goes straight to the root zone. Adjust the amount you apply according to the packaging so you don’t overdo it, which can lead to excessive foliage growth. Any time you’re feeding your bushes, the nitrogen level is the most important number to pay attention to. Keep an at-home soil testing kit to monitor levels. 

Feeding brand-new blackberry bushes: Break up the application into three separate feedings: the first about two weeks after planting, four weeks later, and then four weeks after that. Feeding at the time of planting is not recommended. Allow plants to get settled in before introducing nutrients. 

Feeding established blackberry bushes: Feed annually each spring using a balanced 10-10-10 fertilizer. ½ to ¾ cups per 100 square feet should do. Apply a fertilizer high in potassium mid-spring to improve yields, flavor, size, and color. Stop feeding mid to late summer to avoid lots of tender, new growth going into winter, which a frost can easily harm. 

Use fertilizers indicated for rhododendrons and azaleas, as they have similar soil fertility needs.

Space Properly 

Spacing will depend on the varieties selected, but give them about 3 to 12 feet of space, with at least six feet between rows. While the recommended spacing may seem unreasonable, remember that you want to be comfortable harvesting, pruning, and caring for the plants in the future. Yields and health may be affected if plants are overcrowded. 

Space semi-erect blackberry varieties at about five feet with rows six to eight feet apart. Suckers from semi-erect are produced from the crown rather than popping up sporadically in the bed. Space erect varieties at three to four feet. 

Growers may practice tip layering as a way to expand their plot, and it’s also a way to control erect varieties that can grow to six to ten feet. Trellis systems should be at least five feet tall. 

Trellis 

How you trellis depends on the variety you selected and its growing habit. You can create a creative DIY trellis system to complement your garden’s aesthetic. A flimsy metal fence meant for cucumbers simply won’t do the trick. Choose something that will support the weight of your plants and fruit loads for years.

Growers may train their plants to grow up a fence, a trellis wall, or a system made from T-posts and wire. Pro tip: Install your trellis system at the time of transplant or when new growth emerges to avoid a situation later that leaves your growing plants unsupported. 

Dwarf, erect, and everbearing varieties may not need to be trellised.

Control Those Weeds 

Blackberries have relatively shallow roots that weeds can quickly take over. Controlling weeds is critical. Clear the raised bed of all weeds before planting. If you have a few weeks to spare before planting new blackberry bushes, cover the area with a silage tarp to prevent new weed seeds from emerging, creating a stale seed bed. 

Cultivate several weeks after planting. Keep your cultivation tool an inch deep or less to avoid nicking blackberry roots. To kick weed control up a notch, lay clean, brown cardboard around your bushes after weeding, layer on compost and straw, and water it well. The cardboard will keep weeds at bay, and as it breaks down, it will add fertility to the soil. Plain old woodchips from a trusted source work well, too. 

Weeds will always be competing for resources like water and nutrients. Keep them in check to make sure your blackberry bushes have what they need. Pro tip: To prevent your blackberries from spreading, monitor for new primocanes or suckers popping up and pull them out. Discard these or gift them to a friend. 

Deter Pests 

Everybody wants to get their hands on sweet, juicy blackberries, including pests! Major blackberry pests include cane borers, aphids, mites, Japanese beetles, sawflies, thrips, and birds. Scout early and take swift action to control them.  

Insecticidal soap sprays and neem oil kill soft-bodied bugs like mealybugs, spider mites, thrips, and aphids. Plant beneficial blackberry bush companions like thyme, mint, and chives nearby to attract ladybugs and to confuse and deter pests. For aphids, mites, and thrips, a strong stream of water from a hose often does the trick.

Install scare tape, insect netting, motion-activated lights, and water sprinklers to deter birds. Keep your garden clear of debris where pests may lay eggs containing future havoc-wreaking generations. 

Decoy animals like coyotes and owls may deter squirrels, deer, and chipmunks, but this can be challenging. Apply blood meal, human hair, or coyote urine around the perimeter of your garden to turn them off. 

Prune Like You Mean It

Pruning is a garden task often at the end of the to-do list. But, failing to prune may cause plant disease, increased pests, decreased yields, and unsightly bushes. Well-kept blackberry bushes are attractive, productive, and healthy! Pruning best practices can be tricky, so I’ll review some basics. 

If you notice scraggly, diseased, or dead canes at any time of the year, prune them off. Periodic maintenance makes the main wintertime pruning a breeze. Remove canes closer than six inches to another cane to allow good air circulation and airflow. Otherwise, pruning timing and style will depend on your selected variety, particularly if you have a summer-bearing (primocane) or everbearing (floricane) variety. Use clean, sharp loppers, and wear gloves if your variety contains thorns. 

When the plant is still dormant in late winter before new growth emerges, prune plants to four to six healthy canes, removing damaged and old canes. Pruning is critical for healthy air circulation, fruit size and yields, sunlight penetration, and ease of harvest. The remaining plant may seem bare, but heavy pruning will encourage plants to focus their energy on these few remaining canes and grow big fruits. 

Similar to tomatoes, remove any side shoots from the lower 18 inches. Lower fruits are tempting to critters and at a higher risk of becoming diseased and shaded. 

Primocane Pruning 

Primocane blackberry bushes bear fruit on the tender, green canes that pop up in the spring, so you’ll receive a bounty in year one. These canes are also called new or first-year wood. As the underground rhizome spreads in subsequent years, these new canes may appear far from the central plant crown. In the first year of growth, bushes will not typically produce fruit. Tip the primocanes back to allow lateral shoots to emerge. These shoots will produce fruit the following year. 

Floricane Pruning 

Overwintered primocanes become floricanes in their second year. Canes from the central plant crown left on to overwinter become floricanes and will bear fruit, dying off soon after. Throughout the growing season, new primocanes will emerge, preparing for the following year’s fruit. Prune often and annually to keep bushes from becoming unruly. Remove floricanes after they’ve fruited. Burn trimmings to avoid the spread of pests or disease. 

Pro tip: If scheduling your prunings seems like a hassle, you prefer a tidy winter garden, or you live in a cold region, “fall-manage” your blackberries by lopping them down to the crown in the fall. This method is most effective with everbearing varieties that fruit on new wood each year. Fall-managed bushes will not have a second harvest each year. If you’re unsure, experiment by trying this method on one bush and monitor its behavior in the spring.