Blackberry Production - the Ins and Outs

Blackberries – both floricane and primocane varieties – are increasing in popularity. The timing of both crops coincides nicely with other small fruit crops whether for U-Pick, roadside stands, or wholesale production.

Below we focus on the basics of blackberry production. Please contact our office for more advanced recommendations.

Site Preparation
Preparations for blackberry plantings should begin at least one year in advance. We advise taking soil samples to get a read on your pH, % organic matter and overall fertility to make any necessary changes. We recommend a pH in the 6.5 – 6.8 range with a minimum of 2-3% organic matter.

A nutritionally healthy planting in a well-drained soil with exposure to air movement is less susceptible to damage from pests and frosts. Blackberries are marginally winter hardy, so choose the location carefully. Blackberries require good internal soil drainage to grow and will perform best in a well-drained sandy loam. Wet soils restrict root growth and respiration, resulting in weak growth and reduced yields. Planting into raised beds is highly recommended to improve soil drainage in the rooting zone, particularly on heavier soils. Selecting a site with a gentle slope (3-4%) and good air drainage will also promote faster drying of foliage, flowers and fruit which will reduce the duration and frequency of disease infection periods. Recommended plant spacing is 3-4 feet in the row and 10-12 feet between rows. 

Drip irrigation is an essential component to successful blackberry production. Plants generally require 1-2 inches of water per week in the growing season and 2-3 inches per week during harvest. We suggest having your local irrigation sales company review your field layout for the best recommendations for your situation.

Choosing a variety
Picking the appropriate varieties for your operation is one of the most important decisions a grower can make. In northern areas, winter-hardiness is a key factor in choosing a variety. As a guideline, most varieties are winter-hardy to 10 degrees.

FLORICANE/SUMMER BEARING THORNLESS VARIETIES

NATCHEZ
Earliest ripening thornless variety with very high production of very large, flavorful berries. As it is semi-erect, it will perform best with a trellis. Zones 5-9.

SWEET-ARK ™ CV. ‘PONCA’
Based on breeder information, one of the sweetest and most flavorful berries with good yield potential and excellent post-harvest fruit quality. Ripens shortly after Natchez, but before Caddo, meeting an important early ripening window. Full description on next page. Zones 6-9.

CADDO
Early results show Caddo ripening between Natchez and Osage with comparable yields to Osage and Ouachita. Full description on next page. Zones 5-9.

OSAGE
Consistently among the best tasting Arkansas varieties. Berry size is medium; vigorous plants may require less nitrogen than other varieties. Its early ripening makes it susceptible to spring frost. Zones 6-9.

OUACHITA
A standard in the industry. A thornless variety with excellent fruit quality with firm, sweet, attractive berries. Ripens before Navaho. Plants are very erect with moderate vigor but lack of winter hardiness does limit it to Mid-Atlantic, West Coast and South. Zones 6-9.

CHESTER
Considered one of the more winter-hardy and productive varieties for northern locations. One of the latest Floricane varieties, Chester produces large, high quality fruit that ripens in early to mid-August. Optimum flavor when fruit is picked fully ripe and holds it’s quality & color through
storage. Zones 5-9.

PRIMOCANE/FALL BEARING BLACKBERRIES

PRIME ARK R 45*
U.S. Plant Patent #22,449

Prime-Ark 45 is a thorny, primocane-bearing blackberry with an erect growing habit. Primocane berries are medium size while floricane fruit is larger. Trials indicate variety is very productive and fruit holds up well after picking making it suitable for shipping. Can be treated as a floricane variety as well with ripening time between Natchez and before Ouachita.

PRIME ARK  R FREEDOM *
With an upright growth habit and excellent fruit quality, Prime Ark Freedom is a variety to try for local commercial distribution. We recommend trialing this variety and experimenting with different tipping heights for maximum production.

Planting & Fertilization
Destroy all wild brambles within 500 to 1,000 feet of your planting site. We recommend planting early in the spring when soil temperatures are in the 45 – 50-degree range. Do not fertilize at planting. Sample your soil the previous year to determine nutritional needs. If needed, once plants are established, apply 20-35 pounds actual nitrogen per acre based on soil type. Higher levels of actual nitrogen may be recommended in subsequent years based on soil tests.

Trellising & Pruning
We recommend all brambles, including blackberries, be supported by a trellis. A trellis keeps canes upright, keeps fruit off the ground, makes picking much easier, and maintains good aeration throughout the planting which helps with disease control.

Nourse Farms uses a rotating cross arm trellis in our floricane blackberry production. This allows us to position canes close to the ground, where they can be covered with a a thick row cover for winter protection, and allows us to grow blackberries in an area where winter temperatures are too cold.

Tipping
Tipping is an important practice for maximizing yields on both Summer-Bearing (Floricane-Bearing) and Primocane (Fall Bearing) Blackberries. On Floricane varieties, tip 1st-year caneswhen they reach 5 – 6 feet in mid-summer. Tipping stops terminal growth and established fruiting laterals. Fruiting 2nd year canes should be cut to the ground as soon as possible after harvest.

Primocane blackberries respond very favorably to double tipping. As the primocanes reach 12”-15” in height, break or cut the top of the tips. This process stimulates earlier fruit development, increases yield and also keeps plant height in check for easier management and harvest. Tip again at 30”.

Pest Management
Good weed control during the fi rst year is essential. Blackberry plants are sensitive to most herbicides during the first few months after planting. Research from Cornell has shown that applying a clean straw mulch (4 inches deep) to newly planted blackberry plants provides good weed control. On heavy soils mulch should be used only in the fi rst year since straw mulch over a prolonged period can encourage the development of root rots. We do not recommend bark mulch or any other mulch material besides straw.

Like any crop, a variety of pests need to be managed to maximize yields, fruit quality, and extend the life of your planting. Based on grower experience, other than Spotted Wing Drosophila which impact later ripening summer and fall blackberries, growers should be concerned with:
• Phytophthora Root Rot
• Botrytis Fruit Rot (Grey Mold)
• Aphids
• Yellow (Late or Fall) Rust
• Mites

Please review our Spring 2018 and other past newsletters onour website or contact your local cooperative extension office for specifics on possible controls.