A Blackberry Pruning Method For High-Flavor Thorny and Thornless Varieties

A Blackberry Pruning Method For High-Flavor Thorny and Thornless Varieties

Annual late winter pruning of blackberries to remove the old two-year canes that fruited the past summer involves a large amount of hard hand labor. As we got older it seemed to take longer and longer each year to complete this annual chore before new growth started each spring. Our joy of hearing the first birds singing in February was dampened by the dread of blackberry pruning!

Advertisement

A couple of years ago, we devised and field-tested a system in hopes of eliminating most of this hard annual pruning work. At our house and garden, we had a smaller planting of Chester thornless blackberries that were several years old. When late winter came I decided to try out a new pruning idea on this small scale before trying it on larger commercial plantings. It is my hope that a lower-labor, easier system of winter blackberry pruning and trellis-free culture might help more growers be willing to begin blackberry production. Eliminating the expense, labor, and management of trellising erect blackberry varieties would make growing blackberries much easier. Our state of Virginia has very few commercial blackberry growers, so urban consumers in most communities have little or no sources of such fresh, ripe, tasty, locally grown berries.

After removing my trellis supports and wires, I used my long-reach, articulating head, motorized hedge pruners to cut all plants of one half of the row length down at ground level, primocane raspberry style. On the other half of that single row, I followed the traditional blackberry pruning method of cutting and removing just the old floricanes that had fruited the previous summer, then topped the young canes at 5-foot height.

Of course, that portion of the row where all canes had been mowed to the ground bore no fruit the next summer. However, for our home use we had plenty of berries for ourselves, our family, and our freezer from the half row that was pruned in the traditional manner. The next year, however, the half row where all plants had been removed the previous year bore a most bountiful crop! Those crowns were rested from one year of not bearing fruit, and they seemed rejuvenated.

With no trellis to interfere or work around, we grind up the cut canes in place with a tractor-mounted rear rotary mower set high for the first pass, low for the final pass. Then, as new growth emerges from the crowns in early spring, we air-blast spray the entire planting with lime sulfur for disease control.

Even More Benefits

I believe this system may help extend the productive life of the planting due to the resting phase of the crowns. A 10-year-old planting, for example, would have borne only five crop years. To be able to produce the amount of fruit needed each year, you would need to make your planting larger than you normally would if you used conventional pruning to remove just the old canes after their fruiting year. Then, with at least two rows of each variety, cut off alternate rows of each variety each year, so that you eliminate completely all hand removal of old canes.

This pruning system is especially rewarding for growing thorny erect blackberry varieties that are prized for their very tasty, huge berries. For example, the Shawnee and Kiowa varieties grown here seem to be resistant to orange rust and anthracnose, but are very thorny. Yet, our mostly urbanite U-Pick customers reach right into the plants to get those tasty, large berries that quickly result in full containers. The hand pruning and removal of those thorny old canes from our hedgerows of plants always was very difficult, very slow, and often painful. Those thorns grab other canes as you pull them out of the rows and also grab you at every opportunity during cane removal. We had to use long, beekeeper gloves that came up to our armpits, with heavy leather gloves over them, in order to be able to grasp those old dead canes when pruning and removing them from the rows!

This alternate year fruiting, no-hand labor winter pruning system can be helpful to larger commercial blackberry growers to reduce the drudgery, time, and labor (if you can find the workers) needed to maintain productive, profitable blackberry production, especially with thorny varieties that have such high consumer acceptance.

In a personal communication, Dr. John Clark, the successful fruit breeder at the University of Arkansas who has developed many widely planted erect blackberry varieties including the thorny Shawnee and Kiowa, recommended I also experiment with topping his erect blackberry varieties at shorter heights trellis-free, starting at 3 feet height with several summer toppings, and managing for short laterals so that plants do not need trellises for support. At taller heights, tops likely will bend into row middles and may reduce harvest efficiency and summer mowing of grassy middles. Perhaps some erect varieties may be grown at somewhat taller heights trellis-free; time will tell. An alternate-year bearing cultural system with no trellising and no hand removal of dead canes is offset by less bearing surface and possibly lower yields from shorter plants, but may suit many growers. Always try any new system on a small scale first to see if it works for you.

In an alternate-year system, you may still need to do some removal of new, one-year canes occasionally if in-row plant populations become too thick, plus continue to do multiple summer toppings and side hedging of laterals. Yet this system is so much easier to handle, that if it works for you, you too could look forward to late winter blackberry pruning season, a rejuvenating experience for the grower too!