Blackberries Part I
Blackberries are a delicious gourmet treat that may be eaten fresh or used in cobbler, cake, sauce, jelly, jam syrup or even turned into an adult beverage. Blackberries not only hold an honored place on our table but also in our memories as well. For me, one taste of blackberry cobbler brings back childhood summer memories of putting on a long sleeve shirt and securing my jeans above my ankles with bailing twine and heading to the creek to pick wild blackberries that grew abundantly along the creek bank. I was reminded more than once that all this berry preparation was to protect me from chiggers, mosquitoes, and ticks, but I aways seemed to come back from the wild berry patch with more that a few scratches and bites. But all was forgotten with that first taste of hot blackberry cobbler smothered in milk. Blackberries are an excellent fruit for home landscapes, because they are relatively easy to grow in small areas and bear delicious fruit. So when you are planning this year’s garden, don’t overlook one of the unsung heroes of the fruit world – the blackberry.
Blackberries are classified into three types, based on their growth habits:
Erect, which produce self-supporting thorny canes that do not require support. They are the most winter-hardy type and have large, sweet berries.
Semi-erect blackberries include cultivars that are thornless and thorny; they produce higher yields than the erect type. The semi-erect types DO require a trellis of some sort for support, but their fruit is large and can range from tart to sweet.
Trailing blackberries have canes are not erect and are the least winter hardy; some have thorns while others are thornless. They require a trellis and have large berries with excellent, sweet berries.
The Botany of Blackberries
Blackberries typically have perennial crowns and roots that produce biennial shoots. Specifically, the new shoots — called “primocanes”– grow vegetatively the first growing season, then go through a dormant winter season, and then are called “floricanes” in their second year. Floricanes subsequently leaf out, flower, fruit and die during their second year.
Fruit production of blackberries is directly related to primocane growth and vigor. Plants may produce for 15 years if managed well; but the best production is usually during years 3 through 8. Because of the this, site selection is critical.
Plant the Best Cultivars for our Area
There are many varieties of blackberries available. But to be successful, you need to choose varieties that grow well in our area. Bear in mind this crucial advice from the Virginia Cooperative Extension:
“Of the many varieties of blackberries and raspberries available, few have proven totally satisfactory for growing under Virginia conditions. Only top-quality, virus-free, 1-year-old plants of the best varieties should be planted.”
The following chart offers suggested varieties for our area. In addition, a 2014 study of nine varieties of blackberries was conducted by the Virginia Cooperative Extension (“VCE”) and it provides some useful insights on variety selection. “Evaluation of Blackberry Varieties in Virginia,” Ext.VT..ed/HORT-226.
Thornless blackberry varieties have gained popularity with many gardeners because they allow children and adults to pick berries without the concern of being scratched. However, there are some very tasty and productive thorny blackberry varieties.
Information about the recommended blackberry varieties follows:
- Chester is a thornless, late-bearing, semi-erect variety that is high in yields with a medium fruit size. This variety is resistant to cane blight.
- Kiowa is a thorny, early-season variety that bears the world’s biggest blackberry fruit. Kiowa blooms earlier and longer than other blackberry varieties. The berry ripens in early June.
- Natchez is a thornless, early-bearing variety that produces large fruit that ripens in early June. When fully ripened, it is very sweet and tasty. Natchez is a semi-erect variety and needs trellising for improved production and better fruit quality.
- Navaho is a thornless, erect, mid- to late-season blackberry that produces better quality fruits when trellised. Fruit shape is conic, berry size is medium but very firm, and the flavor is excellent.
- Prime-Ark 45 is a thorny primocane variety that produces firm berries, free of molds and diseases. Berries are large in size with good flavor and are suitable for long-distance shipping.
- Prime-Ark Freedom is the world’s first thornless primocane-bearing variety, released in 2013. This is an erect type that produces very large fruits and has good flavor. The fruit is harvested in the fall and is good for fresh consumption. As a primocane-type blackberry, the Prime-Ark Freedom can produce two crops per year.
Regardless of the variety, it’s best to purchase certified disease-free plants from a nursery. Plants from a friend or neighbor could introduce root rot organisms or viruses into your garden.
Getting your blackberry patch started right is essential. This is one crop where carefully following instructions will truly be worth it. Here’s how the experts at Virginia Tech put it:There is probably nothing that causes more disappointment and failure in small-fruit plantings than the lack of careful preparation and attention to detail at the time the plantings are established.
Blackberries need full sun, at least 6 hours, and tolerate a wide range of soils as long as the soil drains well. Blackberries are sensitive to wet soils. Therefore, drainage is an important factor to consider when you are selecting a site. If blackberry plants are in waterlogged soils for more than a few days, they can die a slow death from lack of aeration (oxygen) or from subsequent attack by root diseases such as Phytophthora root rot. Sometimes you can improve a less desirable site by tilling and amending the soil with organic matter — compost or aged manure — and building raised beds. Blackberries do best in soil that is rich in organic matter.
The pH of the soil should be in the range of 6.0- 6.5. A soil test should be performed before planting. Avoid planting blackberries in a location occupied in the prior two years by any members of the nightshade family — tomatoes, potatoes, eggplants, pepper or other brambles. Members of the nightshade family could transmit verticillium wilt to your new blackberry plants. Also, wild blackberries and raspberries can harbor diseases and pests, so pick a location as far away as practical from any these wild relatives.
Blackberries have traditionally been sold as bare-root plants, though some producers are now selling container-grown plants.
Blackberries should be planted when dormant — in late fall or early in spring, about four weeks before the average date of the last frost. Work the soil as for garden vegetables, particularly where the plants are to be set. Bare-root plants are best planted in early spring. Container-grown plants may be planted any time between early spring and late summer. Both bare-root and container-grown plants should be set 3 feet apart within the row. If you are planting more than one row, allow 4 to 6 feet between the rows. Plants that are crowded will not produce as well.
For each plant, dig a hole slightly larger than the spread of the plant’s root system. Place the plants at about the same depth they grew in the nursery. The crown should be at least 2 inches below the soil line. Spread out the roots and firm the soil carefully around them to eliminate air pockets. Do not allow the roots to dry out. Backfill with soil and cut the canes down to within 2 to 4 inches of the soil. Water the plants thoroughly.
Most blackberry plants come with a portion of the old cane attached. This can serve as a “handle” in setting out the plants. Soon after new growth begins, the handle can be cut off at the surface of the ground and destroyed as a safeguard against possible anthracnose infection.
To maintain plants, be sure to water in dry weather and use mulch to conserve soil moisture and control weeds.
Blackberries perform well in soils containing 3 percent or more organic matter. Organic matter in the soil can be maintained using a permanent mulch. Mulch should be applied soon after setting the plants and maintained throughout the life of the planting by replenishing annually or as needed. Hardwood or softwood bark should be applied at least 5 or 6 inches in depth. If mulch material is unavailable or if cultivation seems necessary, keep the cultivation very shallow 1 to 2 inches to avoid disturbing the roots and repeat cultivation as often as necessary to control weeds.
Blackberries are easily injured by too much fertilizer. Apply no more than 5 pounds of 10- 10-10 or the organic equivalent per 100 linear feet of row the first year, and no more than 10 pounds per 100 linear feet of row in subsequent years. Apply fertilizer only in the early spring before flowering. Apply the fertilizer evenly to the soil surface in an approximate 3-foot-wide band over the entire row. Because brambles have shallow root systems, allow the fertilizer to remain on the soil surface to avoid damaging the roots. Avoid using fertilizers that contain chlorides. But remember, do not over-fertilize because that can lead to too much vegetative growth, burning of foliage, injury to roots, a decrease in fruit quality, and an increased risk of diseases. A soil test should be performed every 2-3 years; the report will alert you to any nutrient deficiencies.
A simple trellis, used in many home gardens, consists of two wires stretched at 3- and 5-foot levels between posts set 15 to 20 feet apart. Fruiting canes are tied to these wires in the spring. The erect varieties are tied where the canes cross the wires. Canes of trailing varieties are tied horizontally along the wires or fanned out from the ground and tied where they cross each wire. Trellising keeps the berry patch neater, making cultivation, mulching and harvesting easier.
Pruning Erect Blackberry Varieties
In late winter or early spring, prune out dormant floricanes that are diseased, damaged or crowded, leaving four to six healthy canes per plant. Side branches also need to be pruned to a length of 12 to 15 inches to encourage larger fruit. When new primocanes reach a height of 30 to 36 inches, pinch off tips of the new canes to encourage side branch growth and development. Immediately after harvest, the floricanes of erect blackberry varieties should be cut down to the ground. Remove the pruned material from the garden and destroy it.
Semi-erect and trailing blackberries
During the first growing season, semi-erect and trailing blackberry primocanes do not need to be trained to a trellis. However, after the first season, semi-erect thornless blackberries and trailing blackberries must be trained on trellises to assure clean, disease-free fruit and ease of picking.
During the second season, before bud swell, bring floricanes up to the trellis wires and tie them individually with soft string; alternatively you can use plastic tape from a hand-held device specifically designed for tying brambles and grapes. The lateral branches are pruned to 10 to 12 inches at the same time.
Often only a small crop is available for harvest in the year after planting. For this reason, some gardeners cut back to within several inches of the ground canes that would have otherwise fruited. This helps the plants become better established by preventing the severe drain on their productivity that results from fruiting. This practice favors the development of sturdier, more fruitful shoots in the subsequent year.
In the second and succeeding years, new shoot growth is more vigorous. These shoots should be tied to the trellis as soon as they have reached a height of 4 to 6 feet. Fan the canes out from the ground and tie them where they cross each wire. Avoid tying canes in bundles. In summer, as soon as the last berries have been picked, cut out all the old canes. Do not remove new canes that have come up since spring, except to thin to four to eight shoots per crown. The best shoots should be selected so that wires are well covered with evenly spaced shoots. Broken shoots or those too short or too weak for training should be removed.
Ordinarily, no further summer pruning is performed on semi-erect thornless blackberry varieties. However, research indicates that there are potential benefits from periodic summer topping to encourage more lateral branching and the development of shorter, more compact plants.
The berries are ripe when the fruit is fully colored and they come off the plant easily. The best time to harvest is in the morning, during cooler temperatures, but after the dew has dried. After the berries are picked, they should be refrigerated immediately since they can only be stored for three to four days in the refrigerator. Another option is to freeze the fruit and use them at a later date.
With a little effort and the right cultivar, you could be enjoying blackberries for years to come. I should caution, however, that blackberries are very addictive and everyone in the neighborhood will be asking for a sample!
Thanks for stopping by The Garden Shed; we look forward to your visit next month, when we will be examining potential diseases and pests that may be lurking in the blackberry patch. Until next month, happy gardening.
“Small Fruits in the Home Garden,” www. pubs.ext.vt.edu/426-840
“Meet Richard Jackson,” Central Virginia Ag Spotlight, blogs.ext.vt.edu/central-virginia-ag-spotlight/2013/08/29/meet-richard-jackson/