Cold weather and blackberry and raspberry bud damage 2007

Blackberry bud damage in April 2007. Note that the primary buds were killed (browned leaves) and secondary buds growing (green leaves).

After an abnormally warm March, April is decidedly cooler in NC. Blackberry and raspberry plants have broken bud and many are beginning to flower. Temperatures are expected to be quite cool these next few days, with temperatures predicted to be 38F in Raleigh and 33F in the Asheville area according to Accuweather. So growers in western NC should be paying close attention to their weather this week.

Although we don't have data on critical temperatures for blackberry, we expect that damage due to cold would be very similar to strawberry. Tighter buds are less vulnerable, and open blossoms are the most vulnerable. These temperatures are:

Tight Bud: 22F
Popcorn stage: 26F
Open Blossom: 30F

Strawberry growers can use rowcovers or irrigation to protect open blooms. Blackberry growers do not really have these options. Rowcovers would be very difficult to spread over the rows. Overhead irrigation adds ice and therefore weight to the canes and will cause them to break.

We experienced a similar situation in 2007. There was lethal damage to primary buds. Fortunately, secondary buds broke soon after the primary buds were killed and the secondary buds produced approximately 70% of a full crop. Five to six weeks after the freeze, the secondary buds were open and you could hardly tell there was any damage earlier that year. Laterals were longer and harvest was later, I think it was at least 2 weeks. Given that we were early, this delay if it happens may not be a bad thing, we may  be able to reset our harvest to the normal dates.

For some insight into what happened in 2007, here is a link and some pictures.
http://www.ces.ncsu.edu/disaster/freeze/BlackberryRaspberryAssessment.pdf

There is also more information on strawberry protection and critical temperatures on the strawberry portal.
http://www.ncsu.edu/enterprises/strawberries

Blackberry crop damage spring 2020

Over the last week there have been cool temperatures at night that have damaged the blackberry crop. The crop in some areas was 10 days to 2 weeks earlier than usual. This year we saw damage to the primocanes, something that we have not seen before. Thanks to the many growers I have talked to over the past couple of days for sending in the pictures below.  My impression is that the site and not cultivar has more to do with damage. Higher sites on the same farm incurred less damage. Also healthier plants sustained less damage.

Flower bud damage
The first image below are from a field visit a few years ago. The first image illustrates how a fruiting lateral looks fine on the outside, however once you slice open that same shoot, you can see that many of the centers (technically receptacles) of the flower buds are black. If the centers of the buds are black, they will not develop into fruit. If they are green, the fruit will develop normally.

On most farms, the crop this year was further along and the damage is easier to spot, no need to cut open the buds. The blackened centers are the receptacles. Culitvars from top to bottom are: Prime-Ark 45, Natchez, Osage and Freedom.

Prime-Ark 45

Natchez

Osage

Floricane crop of Freedom. Date is not correct.

Damage to primocanes
This year we saw damage to the newly emerged primocanes.  We think that the winds that came through over the last week made the plants more vulnerable to the cold temperatures. The damaged tissue will die. However, there are still buds on the lower canes and they will emerge and start growing. The response of the plant will be similar to tipping. 

Traveler cane damage.

Traveler tip damage

Freedom tip damage.

Freedom leaf damage.

What to do this year?

• Wait a few days to determine the extent of the damage. Some areas in the region may sustain further damage this weekend and early next week.
• Secondary buds near the base of the primary shoots may start to grow into a secondary shoot. Here is a link to secondary bud information on this blog. The secondary buds/shoots are often very fruitful, and will produce a later crop. https://teamrubus.blogspot.com/search?q=secondary+buds
• When damage was severe, prune out the entire canes, removing all the dead flowers and the canes that they are attached to. 
• In all cases, maintain a fungicide program, the dead primocane and floral bud tissue in the field will be susceptible to additional disease infection.  

What to think about for the future? 

• Site selection. A few feet in elevation can make a big difference.  There are several online resources that discuss elevation. Here is an example for vinyards. http://www.evineyardapp.com/blog/2019/07/03/how-to-prevent-vineyard-frost-damage/
• Insurance. We have experienced cold damage to the blackberry crop frequently enough that this may be a good investment.
• Wind machines. Peach growers use these in parts of the state. They can be a "valuable tool for frost protection in areas where atmospheric temperature inversions occur during radiation freeze events. The warmer air inversion layer typically occurs at about 40-50 ft, and wind machines 30 ft tall with 18-foot blades mix the warmer air from the inversion with cooler air around the vines. One wind machine typically can provide 1-3ºF of warming for about 10-12 acres" (https://grapes.extension.org/frost-injury-frost-avoidance-and-frost-protection-in-the-vineyard/
• Heaters. Growers can buy commerical heaters or burn items such as large bales of hay. Both options are generally expensive and can be a source of pollution.
• Bare soil or closely mowed cover crop. Bare soils have a large heat capacity, during the day they can capture and store considerable heat. https://www.canr.msu.edu/news/bare_ground_is_warmer
• Shift type trellis and row covers. Growers in the midwest utilize the RCA or shift type trellis in combination with row covers to protect their crop in the winter. https://content.iospress.com/download/journal-of-berry-research/jbr044?id=journal-of-berry-research%2Fjbr044

Thanks to the many growers and to Karen Blaedow, NCCES Henderson County agent who shared their images with me.

Frost 2012 damage to blackberry crop

I was able to visit blackberry growers earlier this week in Western NC.  The current situation is very complicated. I saw a lot of flowers and buds with blackened centers (Figure 1). The center part of the female part of the flower, (technically the pistal), it is attached to the receptacle. Both of these flower parts form the blackberry fruit that we eat, and....both were damaged.

Temperatures. Temperatures dipped to 25-27 F degrees and stayed there for 4-6 hours depending on location the first night, but temperatures likely varied due to location as was evidenced in variation in the amount of damage we saw. (In 2007, it got to 20 F and was widespread across the entire state, damage was severe and killed the entire fruiting shoot).

Crop stage and location. According to most growers, the crop was about 2 weeks early, so all cultivars were well ahead of their normal schedule and many were flowering.   Natchez was at or near full bloom and Ouachita had some open flowers and many flowers that were at popcorn stage. Navaho was behind with just a few open flowers. However, these stages varied depending on the location of the field, location within the field (higher spots had less damage), and location within the canopy (upper wire had more damage than lower wire). 

Crop damage. Damage ranged from very little to severe depending on the location  and cultivar.  In some cases, just the king flower was dead (Figure 2). In other cases, flowers only in the upper portion of the canopy were damaged. I estimate that in some severe situations, there was 80-90% damage and in others only 30-40% damage. 

As I mentioned above and in earlier posts, the 2007 freeze killed the entire primary shoot and the secondary buds emerged and were able produce a crop. However, this year only flowers were damaged, the primary shoots are still viable and they will likely remain attached to the canes. This will likely inhibit the growth of the secondary buds and the crop that they would produce. 

Figure 1. Blackberry flower after 2012 frost. Photo courtesy of Amy Lynn Albertson.

Figure 2. Navaho fruiting shoot. Area circled shows king fruit dead, but subbordinate flowers are viable. 

What to do this year? There are a couple of options, these are some that come to mind at this time.

• You could just wait and see what happens, some buds lower on the primary shoot may not have sustained damage as is seen in figure 2. They will produce fruit, in general the tips of the shoots have the most fruit, often 3-5, while lower down the shoots, only one fruit per node is produced. 
• Prune off primary shoots. You would have to do this close to the cane, but be careful not to prune or damage the 2nd bud (leave approx 1/4 inch). This MAY allow the secondary buds to develop.
• Prune out the entire canes, removing all the dead flowers and the canes that they are attached to. 
• In all cases, maintain a fungicide program, in the first two scenarios, you will have more dead tissue out there that will be susceptible to disease infection.  

Future? Wind machines or helicopters may help if inversions are present. Helicopters or wind machines are often used in peach orchards and grape vineyards. When inversions are present these machines are able to mix the air,  bringing the warmer air down and mixing it with the cooler air, and keeping the temperatures above lethal stages. 

We are also evaluating a movable trellis. This trellis can shift positions. So when it gets cold, the trellis can be laid down and row covers can be placed over the entire row. Finally, we can hope that we are not 2 weeks early in the upcoming years. The earliness of this years crop really elevated the amount damage we saw.

2014 Starting off COLD

January 1, 2014 Blackberry Crop Update:

Short version:

Buds are tight and still developing.
Chilling has not been met for most cultivars (500 hrs in Salisbury).
Low temperatures predicted in the next 10 days are nearing the level that we have some concern about damage.


Longer version: 
Bud Development. We are heading into the coldest part of the year and the blackberry and raspberry buds are tight and are at the hardiest stage of their lifecycle. Research done by Takeda and others in 2003 (http://www.ars.usda.gov/SP2UserFiles/Place/19310000/FTakeda/2003JASHS-blackberrypaper.pdf) followed stages of bud development of both thorny and thornless blackberry cultivars. In general in January buds are at stages 4-6. At this stage, the flowers are still developing, and the most terminal flower buds are furthest along.  See the table 1 below for a detailed description of the stages. So, I dont think that the buds have fully developed. Will there still be some damage? Possibly. I will be monitoring the situation. The good news is that we know that there are secondary buds that can produce nearly a full crop. 










Chilling. We have accumulated 508 hours of chilling as of today at the Piedmont Research Station in Salisbury, NC. This is based on the model found at http://nc-climate.ncsu.edu/cronos/blackberry. The model we use accumulates 1 chill unit when temperature is between 0 and 7° C. The plants should accumulate several more units this week, despite the predicted cold weather. Most of the varieties we grow are higher chilling and have not yet met their standard chilling units, which are estimated to be between 700 and 1100 hours. http://teamrubus.blogspot.com/2012/02/chillin-in-nc-part-2.html

Low temperature damage? Michelle Warmund did some research several years ago and found that with eastern types of blackberries, buds at this time of year have reached their maximum hardiness and are killed at −9 °F.  While the types grown in the western part of the country are often damaged when temperatures reach 12 °F. However, we have observed damage to plants at the Upper Mountain Research Station in Laurel Springs to eastern types when temperatures dipped into the single digits. However, I think most of the damage we saw occurred later in the spring when the flowers were more fully developed. 

What to do?

Monitor your crop. Monitor the temperatures. 

Walk through your fields now and look at buds. Are they tight? Slice a couple open longitudinally and see if they are white and green inside, this is a healthy bud. Black is not good. 

Use row covers? There has been success in the midwest using row covers over the RCA trellis. The trellis is in the lowered position allows for "easier" positioning of the row covers over the trellis. I am not sure how feasible this would be with the trellis system we use in NC. However, if you have a piece, it may be worth pulling it over the entire canopy, sealing up sides and ends. What you want to do is to hold in some heat that is captured during the day. Here is a picture of one of our RCA  plots with row covers.

Blackberry plants recovering after the freeze 2007

Image 1. This is a secondary bud that has emerged (semi vertical green stem). There is a remnant of primary stem, it is the brown nub on the right. 

Image 2. Regrowth of laterals after complete loss of primary buds in 2007. 

Reports are in, there was damage, laterals were wilting in the afternoon at some locations after the  freeze this morning and at other farms there was just bud damage (4/12/12).

Above are some images of the plants a couple weeks after the freeze in 2007. These were in a field  of Arapaho. The remnants of the primocane leaves are on most nodes, it is the brown nub on the right side of the node (Image 1).  A few days after the freeze I was in this field and noted 99% blossom kill and most of the fruiting laterals tissue appeared dead (wilted). I did not look for secondary buds at that time. However, about 2 weeks later, secondary buds were emerging, and I could not find the dead primaries (Image 1).

Another year, another round of blackberry flower bud injury

Blackberry flower bud damage. The centers are the female part of the flower (a gynoecium with many pistals) develop into the fruit. Image above shows 3 out of 5 flowers with blackened centers, indicating that there was lethal damage and fruit will not develop.

Since 2007, just as the NC blackberry industry began to emerge, spring time cold temperatures have killed flowers multiple times (my blog says 2007, 2012, 2014, and 2018, but there may be more). 

Last week, just as we began to think we had missed any chance of bud injury, temperatures dipped to 27F or below.  Blackberry shoots with developing flowers were emerging. There was a wide range of damage, depending on location, degree of bud break, and temperature. Locations and cultivars on the same farm had  in some cases little or no damage to 40% damage to the primary flower buds. 

Growers know what to look for (blackened centers) and had been assessing their crop for the last few days. See image above. In most cases the king or largest flower bud was damaged and some of the secondary and tertiary flower buds also were damaged. The smaller flower buds with green centers will develop into fruit. 

When we see this type of damage, often there are secondary shoots that will emerge and produce flowers a week or so after the initial damage. Look for succulent lighter green often elongated shoots. (Sorry no image, if you have one, send it to me and Ill post it here). The extent of secondary shoot emergence is not consistent. It likely depends on extent of damage to the primary flower buds, cultivar, how well the secondary shoots had developed in the previous year.  We have done some shoot removal studies in the past. These will be summarized in an upcoming post.

Meanwhile here is a link to posts from the past on this topic.
https://teamrubus.blogspot.com/search?q=freeze+

What to look for in terms of cold damage in blackberry and raspberry plants ALSO SEE POST 4/19/12

Image 1. Bronzed flower buds

Preliminary reports from across the state indicate that temperatures did go below freezing. It was 27 F in Davidson County,  and 29 F near Danville, VA.  To determine if your caneberry plants were damaged, you will need to wait a few hours. Around noon, go out to your field and start looking at your buds. Closed flower buds will show a bronzing on the sepals (green outer layer of flower buds) see an example in Image 1. However, there does not to be any visible damage, you need to look inside the buds.

Image 2. Blackberry flower bud after freeze injury. Note that only the ovaries and the receptacle are blackened. 

Slice the buds longitudinally and take a close look. In 2007 we saw that the male plant parts (anthers) were fine in some cultivars, but the female parts were damaged (ovaries) and the receptacle were damaged. See Image 2.

Image 3. Damage to blackberry buds in 2007, the entire flower, anthers, ovaries and receptacle are blackened, in most of these buds. 

However in some cases the entire bud was damaged as is shown in Image 3. In either case, no fruit will be formed.

In a few days you may see entire laterals wilting as was seen in the previous post. If you see this type of damage, you will loose the fruit from those buds. BUT you should see secondary flush of growth and based on what happened in 2007 you will get up to 70% of a full crop, later. Later in this year, means a normal fruiting season, I hope.

If you have damage, what should you do? With all the dead tissue, there is an increased risk of botrytis.  You should apply a fungicide to help keep the infection level down. Maintain your spring fertilizer regime and keep weeds under control to reduce competition for nutrients.

Cold Weather Update

Cold Weather Update January 2026

Gina Fernandez1 and Hannah Lepsch2

1Extension Specialist and 2Research Assistant/PhD student

NCSU Dept. Horticultural Science

A recent storm producing ice, sleet, and snow across North Carolina has raised understandable concerns about potential cold damage to blackberry crops. While colder temperatures are still forecast, early observations and data provide useful insight into what growers should expect and what to monitor closely in the coming weeks.

Ice Storms: Limited Cane Damage Observed So Far

Ice accumulation varied across the state, with some areas experiencing significant  accumulation of over 0.05 inches (Figure 1). In many fields, blackberry canes were coated with ice (Figure 2); however, there is currently no evidence of widespread cane breakage or structural damage from ice weight. Blackberry canes are generally resilient during dormancy, and past experience suggests that ice alone rarely causes major injury.

Figure 1. Ice accumulation across North Carolina,  Jan 24-25, 2026. Courtesy: NC Climate Office. 

Figure 2. Ice accumulation on 'Von' Blackberry, western NC. 

(NOTE: Do not use overhead irrigation for frost or freeze protection in blackberries. Past events have shown that overhead irrigation in the spring to protect buds can increase ice load on canes and result in cane breakage, often causing more damage than protection)  

Cold Temperatures and Bud Damage

To better understand cold tolerance this winter, buds of ‘Ponca’, ‘Ouachita’, ‘Von’, and ‘Galaxy’ were collected in early December 2025 and early January 2026 from three locations in North Carolina: the Coastal Plain, Piedmont, and Mountains. Buds were evaluated for cold injury following exposure to a range of low temperatures. 

Results showed that:

• In both December and January, more than 50% of buds were killed at temperatures near -6°F at the Coastal Plain site.
• In the Piedmont and Mountain sites, bud kill reached 50% at temperatures closer to 0°F 
• 'Ponca' has shown damage in the mid teens.
• Temperatures recorded at these locations have not reached these critical thresholds, suggesting that widespread bud loss is unlikely at this time. 

Additional bud sampling is planned later this week to further evaluate bud survival following recent cold events. 

Cold temperatures and Cane Damage

In addition to bud injury, cold temperatures can also cause damage to blackberry canes. Over the next few days, forecasted lows below 10°F may increase the risk of cane injury, especially in exposed sites or on less cold-hardy cultivars.

Cane damage is not always immediately evident. In many cases, symptoms may take several days or even weeks to appear. Dead or severely injured canes often turn brown or gray, rather than remaining green and healthy. In some situations, damage is not obvious until spring, when floricane buds begin to leaf out but then shoots wilt or collapse shortly after growth starts.

Because of this delayed symptom development, growers are encouraged to be patient and continue monitoring canes as temperatures warm.

Chill Accumulation: Generally Adequate Across the State

Chill hour accumulation is another important factor influencing blackberry performance in spring. As of late January:

• Coastal Plain: approximately 673 chill hours

• Piedmont: approximately 861 chill hours

• Mountains: approximately 893 chill hours

Most blackberry cultivars require 300–900 chilling hours, indicating that chilling requirements have largely been met across North Carolina. Adequate chill accumulation supports uniform bud break and flowering as plants move out of dormancy. 

Deacclimation: Why Spring Buds Are More Vulnerable

As winter progresses into late winter and early spring, blackberry plants begin to deacclimate, meaning they gradually lose cold hardiness as chilling requirements are met and buds prepare for growth.

Because of this:

• Buds become more sensitive to cold as spring approaches

• Temperatures that would not cause damage in mid-winter can be damaging later

• Spring killing temperatures are higher than winter killing temperatures

This is why late winter and early spring freezes often cause more visible damage than colder mid-winter events.

What Growers Should Do Now

• Monitor forecasted low temperatures closely, especially over the next several days

• Delay pruning decisions, particularly in colder regions, until cane and bud survival can be assessed

• After a period of warmer weather, cut buds and canes to evaluate tissue color, healthy tissue will be green, while damaged tissue will be brown or black (Figures 3 and 4).

Figure 3. Primary bud of blackberry is brown/black and is dead. Note that the secondary bud is still green. 

Figure 4.  Blackberry cane showing browning just under the bark, this is vascular damage. 

Bottom Line

Although winter weather has been challenging, current data suggest that temperatures so far have not been low enough to cause major bud loss in most areas of North Carolina for most of the cultivars we studied (except 'Ponca'). Bud and cane injury remains a possibility following upcoming cold nights and throughout the spring, but symptoms may take time to appear. Continued monitoring over the next several weeks and months will be key.

Additional updates will be shared as new data become available.   

Budbreak in NC

It's been a busy spring here in NC. Lots of cold weather has left small fruit growers with some sleepless nights. However, spring has arrived and buds are breaking.

Here is a picture of Navaho bud break at the Vollmer Farm in Bunn NC on Monday. I took my HS 422 class there to see strawberries, blueberries and blackberries. We sliced open several blackberry buds, like the one in the picture below and did not see any damage.  The crop appears to be later than usual,  we usually see leaves that are larger and in some years, flowers have been open by the 1st of April (no fooling').

Navaho bud break March 31, 2014, Bunn NC.

The week before, I participated in the Foothills Farm School, and as part of that training for beginning and transitioning farmers, we visited Maple Spring Farms in Dallas NC. They are one of the few farms that has matted row strawberries and Kiowa blackberries. Their Kiowa blackberries were at about the same stage of bud break as the farm in eastern NC. We did see some buds with damage. We also saw secondary buds, so they should still have plenty of berries. 

Kiowa budbreak, March 27, 2014, Dallas, NC.

Cane damage, what to do?

Protecting blackberries from winter cold with straw mulch. Photo credit: unknown at this time, will update when I figure out its origin.

This year we have seen damage to canes and buds....here are some suggestions on how to manage the crop for this upcoming growing season.

If you have CANE Damage:
First, determine extent of the injury to your canes.

If canes are completely killed to ground, remove them as they will be sites for disease infection. Once they are removed, you will need to manage the emerging primocanes. There will likely be lots of them and they will grow quickly.  Tipping may be needed more frequently.

If canes are damaged on the upper portions, remove the damaged portions, as they will be sites for disease infection. This is of course dependent on if you have labor and how much time it will take to remove the damaged portions of the cane.

If canes are damaged in spots, the plant will have reduced capacity to provide nutrients to the developing laterals, because of damage to vascular tisse (see figure 3 in the previous blog post). I talked to Dr. Bernadine Strik. OSU Berry Crop Extension Specialist,  and this was her suggestion:
" If canes or the bud base are damaged and there is lateral growth, these laterals may “collapse” – grow well and then wilt. While it’s hard to deal with bud base damage, if there is partial cane damage, foliar fertilization to support lateral growth with the cambium of the cane has time to repair can work. We have resisted putting specific recommendations of foliar feeding during delayed dormant and fruiting lateral development stages, because it would be possible to do “too much” and burn the young leaves. This would  be a concern. Also, foliar feeding will not “solve” problems with poor bud break or “fix” canes that are damaged. It’s not a miracle cure. With that said, if there is partial cane damage and the cane is thus limited on translocation of mobile nutrients, foliar feeding would help get  the laterals through the early development period. I would recommend a low foliar rate of N (e.g. 5% urea) as well as Ca. It’s hard to mix Ca with K, but K might be needed also (caution on not applying too high a rate as this will burn leaves). I would apply a foliar every 2 weeks until first bloom."

For management of diseases, make sure you stick to the recommended spray program and watch out for grey mold (botrytis).

Bud Damage:

We have had this occur in the past, both in 2007 and 2012. If only the primary buds are killed, there may be fruit produced from secondary buds. Here are some links to previous posts regarding bud damage:

http://teamrubus.blogspot.com/2012/04/freeze-2012-field-visits.html

http://teamrubus.blogspot.com/2012/04/cold-weather-and-blackberry-and.html

Rotating Cross Arm Trellis August update

Figure 1. Rotating cross arm trellis in August.

Earlier this spring, I posted a picture of a new trellis we are trialing at one of our research stations (http://teamrubus.blogspot.com/2012/05/rotating-cross-arm-trellis.html). Above is a picture taken on August 22, 2012.  We have 3 cultivars on each section of this trellis, Apache, Ouachita and Von (aka NC430).

Figure 2. Training of primocanes on wire. 

The second and third images show how we trained the primocanes to the bottom wire as they emerged from the crown. The canes were tied to the low horizontal wire. This encouraged buds that were on the horizontal wire to start growing. These secondary buds will produce canes that are very productive and are easier to train to the trellis because they are narrower. Fumi Takeda has done some very nice work describing the productivity of the buds in this paper. Here is a link to a summary of this work.
http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=281491

Image 3. Close-up of training of primocanes on the horizontal wire. Photo: Fumi Takeda. 

To get the entire article, you will need to become a member of NARBA. (http://www.raspberryblackberry.org/subtopics.cfm?topic=Membership)

March Madness in North Carolina...berry fields

It is March and if you live in North Carolina you know it is March Madness season. This year we have the usual NC basketball teams (who shall not be named) making the Sweet 16/Elite8/Final 4. However, there is some "maddening" things happening in the berry fields as well.  Warm temperatures in February and March stimulated bud break, and were followed by some very cold temperatures (in the teens) March 22-24.

Blackberries throughout the Carolinas were in various stages of bud break.  In research plots, the most advanced cultivars (Ouachita and some numbered selections) were about 1/4" to 1/2" elongated.  King flowers were killed in most of the more elongated buds.

A grower field tour last week in the Lincolonton NC area,  revealed that earlier flowering cultivars like Ouachita and Kiowa had king flowers and some of the secondary flowers killed. There was less damage to Navaho and Von both later flowering/fruiting cultivars. There was no green/brown cane discoloration that would indicate cane vascular damage, at least none that was evident at this point.

We will know the extent of damage as the buds continue to elongate over the next couple of weeks.  Although the temperatures were quite low, damage does not appear to be as bad as other years.

Navaho blackberry plants, buds are less than 1/4" elongated. Photo taken 3/23/17. 

Ouachita blackberry canes, showing 1/4" or more elongated buds. Photo taken 3/23/17. 

Assessing cold damage in blackberry and raspberry buds and wood at annual NC grower meeting

In early January, at the SE Vegetable and Fruit Expo in Savannah, GA, we set up a microscope and a magnifying glass (the kind you get in a craft store) to look at bud damage in blackberries. Most of the buds that I sampled looked good. http://teamrubus.blogspot.com/2014/01/buds-look-good.html

On Feb 6, 2014 we be looking at more samples at the annual meeting of the North Carolina Commercial Blackberry and Raspberry Association, in Shleby, NC. (Contact Daniel_Shire@ncsu.edu for meeting information). We will be looking at  samples collected  from our research blackberry and raspberry fields.

You are welcome to bring in some samples from your fields. We may not get to all of the samples, but we will train you to look at your own samples, so you can sample your own fields on a regular basis.

If you want to bring in some samples or prepare samples for evaluation at home, here is the protocol (courtesy of Michelle Warmund, University of Missouri):

• cut 3-4  8" cane sections from a low, mid parts of a main cane and some laterals from the fruiting area
• place each group of canes in  in a zippable gallon size plastic bag
• label each bag with name of cultivar and where the cane was taken from the plant (low, mid, laterals)
• store at room temperature for 4-5 days before the meeting.

At the meeting we will cut canes and check for injury symptoms. Dead cane sections and buds will have oxidized and turned brown after storage for 4-5 days in the zippable gallon size plastic bag. The sections from the lower and mid cane are needed to assess potential damage primarily to the canes. We will look at bud and cane damage on the laterals.

Here are some examples of bud and cane damage in West Virginia at the USDA Appalachian Fruit Research Station in Kearneysville, WV. The photos taken by Dr. Fumi Takeda.

Winter injury to blackberries. Plants with shriveled floricanes and primocanes are green and healthy. Photo: Fumi Takeda 

"Bark" scrapped off, showing oxidation of cambial/vascular tissues. Photo:Fumi Takeda

Primary bud is damaged as indicated by necrosis of partially differentiated inflorescence axis. Secondary bud is still undifferentiated, no sign of damage. Photo:Fumi Takeda.