Trellising, training and pruning brambles are important for long term quality berries and crop productivity. Correct trellising and pruning timing and technique allow for manipulation of cane numbers and growth. This will yield improved fruit quality and size, lower disease susceptibility, ease of harvest and better spraying efficiency.
These are the basics. For more advanced trellising and pruning techniques, call us for recommendations.
GENERAL TRELLISING INFORMATION
We recommend all brambles be supported by a trellis. A trellis keeps canes upright and fruit off the ground, makes picking far easier, reduces wind damage and maintains good aeration throughout the planting which helps with disease and Spotted Wing Drosophila control. We have been successful using a T-trellis which supports 2 wires 12” apart at 3.5’ to 5’ above the ground (see diagram). Trellises may be temporary to facilitate
mowing in the spring. We suggest installing 6’-8’ long metal fence posts 1 1/2’ - 2’ into the soil. Bolt on a 12-18” piece of angle iron to create the horizontal crossbars. Drill hole on each end the angle iron to secure twine. You may also use wood posts and cross bars. The T is made by thru-bolting 12” – 18” two-by fours. Posts should be spaced 15’ – 25’ apart along the row. Rows longer than 100’ should have pressuretreated 4” x 4” end posts. Monofi lament trellis wire should be considered instead of twine.
Primocane-Bearing (Fall-Bearing/Everbearing) Red & Yellow Raspberries
Varieties: Polana, Joan J, Polka, Himbo-Top, BP-1, Caroline, Heritage, Double Gold, Anne
Installation is usually done sometime in July after raspberries produce their first flowers. Poly twine works well and comes in many sizes, we recommend #450 1-ply. We remove twine and posts after plants have seen 2 freezes.
The main crop is borne in the late summer and all on the tips of canes that emerge in the spring and grow throughout the summer. Most fall-bearers will produce the best crop if canes are cut down each year and only allowed to fruit in the fall. For fall production only, prune or mow all the canes to the ground in late winter/early spring, this is especially beneficial in colder areas. Besure to cut the canes as closely as possible to the soil surface, leaving little or no stub above the ground. Timing is also very important. Carbohydrates move from plant leaves into the crown in autumn, and from the crown to the buds in early spring. If canes are cut before all the carbohydrates reach the crown in autumn, the new canes may not be as vigorous the following year. Canes can also be cut too late, after carbohydrates have move to the buds. From December – February, most carbohydrates are in the crown, so this is the ideal time to cut canes.
In order to develop two crops, the planting must be pruned as summer bearing varieties. When allowed to stand through the winter, a second crop is produced early the following summer, lower on those over- wintered canes. After harvesting the summer crop, cut the over-wintered canes to the ground, leaving the new primocanes to produce the fall crop.
Floricane-Bearing (Summer-Bearing) Red Raspberries
Varieties: Prelude, Boyne, Killarney, Nova, Latham, AAC Eden, Encore
Some taller-growing varieties, such as Nova and Prelude, might benefit from a T-trellis with two horizontal crossbars – one at 3’ – 3.5’ and one at 4.5’ – 5’. Removing leaves from lower 18”– 24” will allow better air circulation, while increasing light penetration for new primocane growth.
These varieties carry one crop of berries during the summer on over-wintered canes. For best yields, immediately after harvest, cut the canes that carried fruit as close to the ground as possible. Thin remaining new growth to 6 – 8 strong, healthy canes per funning foot of row. In late fall, cut canes down to 4.5’ – 5’ to manage the picking height.
Floricane-Bearing (Summer-Bearing) Black & Purple Raspberries
Varieties: Bristol, Jewel, Mac Black, Royalty
Black and Purple raspberries are best trained to a 2 or 3 wire trellis with the support of a 4”x4” every 25 feet (see diagram). Attach the main canes to the wire with a clip or a slightly loose zip or twist tie.
Black and Purple raspberries break buds from their crown or base and send out few, if any, suckers. Prune plants to 4 – 6 canes per hill. These plants respond well to tipping, where the first year canes, primocanes, are pinched back (remove about 2”) as they reach a height of 5’ – 6’ through July and August. This practice encourages fruiting lateral branches to break from the main cane and also keeps plant height in check. Laterals should be pruned to 6” – 8” in the late fall. Pinching back laterals can help increase berry size and increase winter hardiness.
Floricane-Bearing (Summer-Bearing) Blackberries
Varieties: Natchez, Caddo, Ouachita, Triple Crown, Chester
A trellis or staking is highly recommended for semi-erect or trailing blackberries in order to keep fruit clean, maximize air circulation, and minimize cane breakage. Blackberries like black raspberries are best trained to a 2 or 3 wire trellis with the support of a 4”x4” every 25 feet (refer people to diagram under black raspberries). Attach the main canes to the wire with a clip or a slightly loose zip or twist tie. Sometimes thornless blackberries are managed in a “staked-hill” system. Set 5’ – 6’ tall 2” diameter stakes approximately 1’ deep and 5’ – 8’ apart in all directions. Set a plant 1’ away from each stake. Secure the primocanes loosely in 2-3 places along the height of the stake. This is an easy to maintain system and can be an attractive addition to the home garden landscape.
Tip 1st-year canes when they reach a 5’ – 6’ height in midsummer or 6” over the top wire. Tipping stops terminal growth and establishes fruiting laterals. Thin the remaining canes (primocanes) to 6 – 8 canes per running yard of row or per hill. Laterals should be cut back to 6” – 8” in late fall. Fruiting canes should be cut to the ground as soon as possible after harvest has completed. Primocanes overwinter and develop fruit the following season.
Considerations: Rotating Cross Arm Trellis
Here at Nourse Farms, we have great success growing Floricane-bearing blackberries on the Rotating Cross Arm (RCA) Trellis, made by Trellis Growing Systems. This trellis, and the pruning and training technique that goes along with it, gives growers the ability to lay their canes down and be covered to increase winter hardiness. This system can also reduce sunscald by forcing blossoms onto one side of the trellis, where the fruit can be protected by the foliage.
The training method for the RCA trellis involves training your primocanes to a low horizontal wire, 18” high, and tipping when canes reach 5’ or the next plant. Laterals are then trained vertically, much in the way that primocanes are traditionally trained. In the fall the posts are rotated down to lay on the ground and are then covered with a heavy floating row cover. In spring, the row cover is removed and the posts are rotated up.
To prevent sunscald, just prior to bloom the posts are rotated so they are parallel with the ground. This causes the blossoms to emerge on the upper side of the trellis. Once bloom has begun, the trellis can be returned to
its standard position, leaving all of the blossoms on the shade side of the trellis and thus protecting them from direct sun exposure and reducing sunscald. This technique also increases picking efficacy as rows can be effectively picked from one side.
Primocane-Bearing (Fall-Bearing/Everbearing) Blackberries
Varieties: Prime Ark 45, Prime Ark Freedom
See Trellising under Floricane-Bearing (Summer-Bearing) Blackberries.
Primocane blackberries respond very favorably to tipping. As the primocanes reach 12 – 15” in height, break or cut 3⁄4” – 1” off the tip to force the cane into branching (laterals).
A second tipping should be performed as the lateral branches reach 30”, again breaking or cutting 3⁄4” – 1” off tips. This process stimulates earlier fruit development, increases yield and also keeps plant height in check for easier management and harvest.
The main crop is borne in the late summer and all on the tips of canes that emerge in the spring and grow throughout the summer. Most fall-bearers will produce the best crop if canes are cut down each year and only allowed to fruit in the fall. For fall production only, prune or mow all the canes to the ground in late winter/early spring, this is especially beneficial in colder areas. Be sure to cut the canes as closely as possible to the soil surface, leaving little or no stub above the ground. Timing is also very important. Carbohydrates move from plant leaves into the crown in autumn, and from the crown to the buds in early spring. If canes are cut before all the carbohydrates reach the crown in autumn, the new canes may not be vigorous the following year. Canes can be cut too late, after carbohydrates have moved into the bud.
When growing Primocane-bearing blackberries, southern growers may benefit from a single tipping at 3’, leaving the laterals untipped. This will delay harvest compared to untipped canes but advance it compared to double tipped canes while also prolonging the harvest.
Primocane-Bearing (Fall-Bearing/Everbearing) Black Raspberries
See Trellising under Floricane-Bearing (Summer-Bearing) Black Raspberries
Tipping or tip pruning is highly recommended for primocane-bearing black raspberries. As the new primocanes reach 3’, pinch or cut the tips to force branches (laterals) to develop. Tipping will delay, but prolong the harvest, increase yield and reduce the arching of the canes and tip rooting. Pruning later in the season decreases the amount of time the plant will have to develop branches. Leaving the primocanes unpruned will allow earlier ripening than the tip-pruning option; but the canes will become tall and arching and will develop fewer berries.