Cane damage to blackberries in some locations

Each year we learn more about growing blackberries in the southern US. In the past,  we have had late spring frosts/freezes that have resulted in bud damage. This year, we are experiencing a new type of winter injury, cane damage (Figures 1- 3). 

It has been cold here, with temperatures dropping to the single digits on several occasions  (Table 1). The cane damage ranges from death of entire canes, death of upper portions of canes (not shown), cane splitting and damage to just portions of a cane, as is shown in Figures 1-3. The range of damage varied considerably, with some sites experiencing almost no damage to some with more than 90% damage.  The severity of damage also varied by cultivar, with Navaho showing most damage. 

Figure 1. Blackberry canes with 90% or more damage to floricanes.  

Figure 2. Cane splitting.

Figure 3. Two pictures of a blackberry canes with cold damage. Arrows indicate region of damage to the same cane.  Left image: arrow points to browned area showing damage to the vascular tissue (xylem and phloem) on the inside of the cane. Right image: damage on the outside of the cane, epidermis is sunken and dark brown. The large crack in the center of the pith occurred when we cut the cane, and is not a result of cold damage.