It has been cold in GA! Sudden temperature drops and late-spring frosts are generally the most damaging, it can be difficult to assess how ‘cold hardy’ our vines are at any given point. And while grapevines are generally more cold hardy than I am (because I am a wimp), there are certain ways you can monitor for damage in your vines. Assessing that damage can help determine whether additional care, pruning adjustments, or other efforts are needed.

How a vine reacts to the cold will depend on several factors. There is more likely to be damage when a vine is not fully dormant and when temperatures drop suddenly. The variety plays a big role, for example, muscadines are generally more susceptible to cold than most bunch grapes. Dormant muscadines generally have a minimum temperature closer to 10 degrees Fahrenheit, while many bunch grapes can handle closer to 0 °F,  and some American bunch grape varieties can handle even colder! Then, healthy, mature vines are much more resilient than stressed, diseased, very young, or even overly-vigorous vines in cold weather.

After a cold event, it can take a few weeks for symptoms to show up, so patience can be necessary.

1. The first area to check is the buds. Grape buds can be the most vulnerable to cold temperatures. Using a razor blade and a hand lens, cut off a tip of the bud. This can be done in multiple sections to see the different sections of the bud. If the buds appear shriveled, brown or blackened, or sometimes even soft and mushy, the buds have been damaged.
2. Green tissue on young shoots or canes can also show damage, where tissue can appear darked, sunken, or otherwise damaged.
3. Examine the trunk, cordons, and canes for cracking and discoloration. If there is cracking, it may be necessary to prune off the damaged sections and monitor the vines for growth later in the year. Especially on grafted vines, monitor for growth that could be coming from the rootstock instead of your chosen scion.
4. Some damage can take much longer to show up, so continue to monitor the vines. Damage can show up later in the season when there is much more canopy than a damaged vine structure can support, leading to a ‘vine collapse’. Additionally, the damage can make vines more susceptible to fungal diseases and crown gall, and other stressors which can benefit from prompt intervention.

If you are checking the grape buds and see damage, there are some pruning adjustments you can make to hopefully counteract some of the yield losses from bud damage. Trimming the buds slowly should first expose the primary, then secondary, and then tertiary buds (since grapes have compound bud structures). The primary buds tend to be the most fruitful, though varieties can vary on how fruitful their other buds can be.

If you are finding only about 0-15% dead primary buds, then you can prune normally. If 15-80% of the primary buds are dead, then keep more buds while you prune. If over 80% of the primary buds are dead, then take a second look for trunk and cane damage and then prune minimally.

Additional Resources!

• Freeze Damage – Previous UGA blog post – https://viticulture.uga.edu/2023/01/freeze-damage/#:~:text=If%20your%20vines%20have%20experienced,will%20need%20to%20be%20replaced.
• Guide to Assess Freeze Damage of Grapevines in Early Summer – Ohio State – https://ohiograpeweb.cfaes.ohio-state.edu/sites/grapeweb/files/imce/pdf_factsheets/Guide%20to%20Assess%20Freeze%20Damage%20of%20Grapevines_Summer_Revised_Final_ID.pdf
• Grapevine Cold Hardiness – Texas A& M – https://aggie-horticulture.tamu.edu/vitwine/2018/05/10/cold-hardiness/
• Grapevine Cold Hardiness – Washington State – https://wine.wsu.edu/extension/weather/cold-hardiness/

Upcoming Events:

In-Person Events!

• Georgia Wine Producers Annual Meeting: February 9-11, The Classic Center, Athens, GA – georgiawineproducers.org
• American Society of Enology and Viticulture – Eastern Section (ASEV-ES) 49th Annual Meeting: July 8-10, in Athens, GA – https://www.asev-es.org/
• Design a Commercial Grape Spray Program Workshops!
  • Thursday, Jan 30^th: Dahlonega, GA –
    • Location: Lumpkin Co. Parks & Rec Building – 365 Riley Rd, Dahlonega, GA 30533 – 9:30 AM-3:00 PM
    • Questions? Contact Clark MacAllister and Nathan Eason. 
      • SIGN UP HERE: https://www.eventbrite.com/e/how-to-design-a-spray-program-for-a-commercial-vineyard-dahlonega-ga-tickets-1115855877969?aff=oddtdtcreator
  • Thursday, Feb 27th: Hendersonville, NC – EVENT RESCHEDULED AFTER INCLEMENT WEATHER
    • NCSU Henderson County Extension Assembly Room, 100 Jackson Park Rd, Hendersonville, NC 28792
    • To sign up or for questions – Contact: Karen Blaedow

Virtual events:

• EVEF 2025 Series: February 18th, 12-1:30PM – Vineyard Floor and Weed Management (sign-up link )
• EVEF 2025 Series: March 11th, 12-1:30PM – Vineyard Disease Management (sign-up link )
• EVEF 2025 Series: April 15th, 12-1:30PM – Vineyard Sprayer Calibration (sign-up link)