The widespread freeze injury observed this spring followed several nights of below-freezing temperatures after unusually warm early-season conditions accelerated bud development throughout much of New Jersey. In many southern New Jersey production regions, temperatures dropped into the mid-20s°F, while in northern areas they were near or below 20°F. Clear skies and calm wind conditions likely intensified injury through radiational cooling and rapid heat loss from actively growing green tissue. Comparable freeze injury has been reported across much of the Northeast and Mid-Atlantic this season, particularly in vineyards.

Damage severity varied substantially across vineyards depending on location, topography, vine developmental stage, and cultivar. Low-lying frost pockets generally sustained more severe damage, while elevated sites and some coastal areas sustained less damage. Vineyards with vines still in earlier developmental stages often escaped damage more successfully than vineyards with actively expanding shoots and flower clusters. Even within the same vineyard block, damage may vary considerably depending on local elevation changes, air drainage, and cold-air movement patterns. Because of this, management decisions should be based on detailed observations and adjusted in light of remaining crop potential and vine recovery. Although crop loss is the immediate concern in many vineyards, freeze injury may also alter canopy development, nutrient demand, disease pressure, and long-term vine productivity.

The full extent of freeze injury is not immediately apparent. Injured shoots and flower clusters may continue to deteriorate for several days after freezing temperatures, and growers should avoid making rapid assumptions about final crop loss immediately after injury. In many vineyards, much of the damage only becomes evident as secondary buds begin to emerge and fruit set progresses. Some vines that initially appeared heavily damaged may still yield partial crops through surviving secondary buds, while others may continue showing delayed injury symptoms over the coming weeks.

Fortunately, grapevines recover from freezes through shoot growth from secondary and tertiary buds within count buds, release from inhibition of basal buds, and development of adventitious shoots from latent buds. These features give vines the capacity for recovery after freeze events.

Primary buds are generally the most productive and account for the majority of crop production. When primary shoots are damaged or killed, secondary buds may emerge within days to weeks, depending on weather conditions and vine vigor. Although secondary shoots often produce smaller clusters and reduced yields, they may still contribute meaningfully to crop recovery in some cultivars. Figure 1 provides an example of freeze injury where a frost-killed shoot from the primary bud is accompanied by new development emerging from a surviving secondary bud.

Figure 1. The frost-killed young shoot (right) of Chambourcin and a new bud developing from the secondary bud (left). Photo by H. Gohil

In many Vitis vinifera cultivars, secondary shoots may support only a fraction of a normal crop. However, several hybrid cultivars may retain greater productivity following freeze injury.

When both primary and secondary buds are damaged, tertiary buds may still produce vegetative shoots. While tertiary growth and adventitious shoots generally contribute little or no fruit, they remain critically important for rebuilding the canopy and maintaining vine productivity for future seasons.

Vineyards may also contain both primary and secondary shoot-derived clusters on the same vine, contributing to uneven crop development and maturity (Figure 2).

Figure 2. Vidal Blanc, a shoot from the primary bud, had a typical cluster; on the same cordon, a shoot from the secondary bud had a smaller cluster. Photo by H. Gohil

As recovery continues, vineyards may contain a mixture of surviving primary shoots, secondary regrowth, and delayed vegetative growth. Uneven canopy development may complicate pest management, fungicide timing, canopy management, and harvest timing later in the season.

Growers should continue monitoring:

• Primary and secondary shoot survival
• Cluster development on secondary shoots
• Variability within vineyard blocks
• Low-lying frost pockets and delayed-growth areas
• Trunk or cordon vascular injury
• Sucker emergence and retraining potential
• Overall vine vigor and canopy development

Management decisions may differ substantially among blocks depending on remaining crop potential.

Although severely damaged shoots may appear unlikely to recover, removing frost-injured shoots too early often provides little benefit and may unintentionally reduce remaining crop potential.

In many situations, allowing vines time to recover naturally is the best approach, particularly when injury severity is still being assessed. Removal of damaged tissue too soon may eliminate secondary or latent buds capable of producing additional growth. Dead or injured tissues frequently dry and detach naturally over time without intervention.

Growers should therefore avoid making aggressive canopy removal decisions immediately after freeze injury unless tissue viability and recovery potential are clearly understood.

Primary Bud Loss with Secondary Regrowth

In vineyards where primary shoots were largely lost, growers should allow time for secondary buds to push before making major management decisions. Depending on temperatures and vine vigor, secondary shoots may emerge within days to weeks following injury.

Although crop potential will often be reduced, canopy development may still recover relatively uniformly. Delayed development should be expected, and management programs may need to be adjusted according to new growth stages rather than original seasonal timelines.

Dead tissues often fall naturally and may not require immediate removal unless they interfere with vineyard operations or pose a disease risk.

Partial Shoot Injury

Freeze injury is often uneven, even on the same vine. Some shoots may experience leaf injury while retaining healthy shoot tips and continue to grow normally. In these situations, little intervention may be necessary.

Figure 3. Epical meristem is actively growing (left) in Marquette and completely frost-damaged in Chardonnay (Right). Photos by H. Gohil

However, when shoot tips are killed, continued development may stop, and secondary buds near the base of shoots may begin to grow instead. Vineyard managers should carefully monitor which shoots remain viable and adjust canopy management accordingly. Careful evaluation of shoot tip survival can help determine whether shoots are likely to continue growing or whether regrowth from secondary buds should be expected (Figure 3).

Because vineyards frequently contain both surviving and injured shoots after freeze events, variability within rows and blocks should be expected.

Severe Injury and Cordon or Trunk Damage

In some vineyards, no primary, secondary, or tertiary growth may emerge from portions of the vine, indicating more substantial injury to cordons or vascular tissues. In these situations, strong suckers emerging from the trunk may offer opportunities for retraining vines for future production. Although current-season yields may be lost, maintaining healthy vegetative growth remains critical for long-term vineyard recovery and productivity.

Canopy management recommendations following freeze injury may differ substantially from those of a normal season. Under normal conditions, shoot thinning improves airflow, reduces canopy density, and enhances fruit quality. However, in freeze-damaged vineyards, excessive shoot removal too early may unintentionally increase vine vigor and promote overly vegetative “bull cane” growth with limited fruitfulness. Retaining additional shoots may reduce excess vigor, help balance vine growth, and preserve vine structure for next season. Decisions regarding thinning should therefore be adjusted according to cultivar, remaining crop potential, pruning system, vine vigor, and recovery patterns.

One of the key management questions following widespread freeze injury is whether vineyard nitrogen (N) programs should be adjusted under reduced crop conditions.

In many New Jersey vineyards, nitrogen applications are not made annually and are often applied only every 3 to 5 years. Excessive vine vigor is frequently a greater concern than nitrogen deficiency, particularly in seasons with abundant precipitation. In addition, vineyard soils with moderate to high organic matter often provide substantial nitrogen through natural mineralization. As a general guideline, approximately 20 pounds of nitrogen per acre may become available annually for each 1% soil organic matter.

Following freeze injury, nitrogen demand may be substantially altered due to reduced fruit load. In vineyards where primary buds were lost and crop potential has been significantly reduced, nitrogen requirements are also likely lower than in a typical production year.

Excess nitrogen application under low-crop conditions may unintentionally stimulate excessive vegetative growth, resulting in overly vigorous canopies and increased management challenges later in the season. Excessive vigor may also reduce winter hardiness and negatively affect vine acclimation as vines enter dormancy.

Growers should therefore avoid making automatic nitrogen applications before crop potential becomes clearer.

Where petiole analysis from previous seasons indicated nitrogen deficiency, some nitrogen inputs may still be warranted. However, management decisions should be adjusted according to expected yield, vine vigor, and vineyard history.

It is also important to remember that much of the nitrogen supporting early-season growth from bud break through bloom originates from reserves already stored within the vine. Because of this, immediate nitrogen applications following freeze injury are generally unlikely to improve short-term recovery.

Nitrogen applications are typically timed from approximately two weeks before bloom through two weeks after bloom. In freeze-affected vineyards this season, delaying nitrogen decisions until bloom may allow growers to better evaluate secondary bud survival, crop recovery, and overall fruit potential before making fertility adjustments.

Reduced fruit load means reduced nitrogen demand. In many vineyards affected by freeze injury, a conservative nitrogen management approach may help avoid excessive vigor while supporting long-term vine health and winter hardiness.

Although immediate concerns following freeze events often focus on crop loss, freeze injury can substantially alter disease risk throughout the growing season. Damaged shoots and leaves are more vulnerable to infection once warm, wet conditions return, while wounds in shoots and permanent wood may provide entry points for pathogens such as Botrytis and grapevine trunk diseases.

Even when crop potential is limited, disease management remains important. Maintaining healthy foliage supports carbohydrate storage, winter hardiness, and next year’s productivity. Disease priorities may shift away from fruit protection and toward preserving canopy health and minimizing inoculum for future seasons.

Remember, long-term vineyard health is the goal this season. Managing diseases that cause defoliation and negatively affect grapevine health remains critical, even in vineyards with little or no harvestable crop.

Key diseases to continue monitoring include:

• Downy mildew
• Powdery mildew
• Black rot
• Botrytis bunch rot
• Phomopsis cane and leaf spot
• Anthracnose in susceptible cultivars

Dense regrowth following freeze injury may increase canopy humidity and prolong leaf wetness periods, creating favorable conditions for disease development. Good canopy airflow and spray penetration remain important, and practices such as shoot positioning and, if needed, selective thinning may help improve canopy conditions. Management decisions should continue to be guided by vineyard history, weather conditions, canopy density, and ongoing regrowth patterns rather than calendar timing alone.

Although freeze injury may substantially reduce crop potential, insect management should not be abandoned entirely. Reduced fruit load does not necessarily reduce insect pressure, and some pests may still negatively affect vine health, vegetative growth, or future productivity.

In vineyards with limited or no crop, management priorities may shift away from fruit protection and toward preserving canopy health, minimizing vine stress, and maintaining productive vines for future seasons. Continued scouting remains essential, particularly as secondary and tertiary growth emerges following freeze injury.

Growers should continue monitoring for key vineyard pests, including:

• Grape berry moth
• Japanese beetle
• Spotted lanternfly
• Phylloxera in susceptible vineyards
• Leafhoppers and other sap-feeding insects
• Mites during hot, dry periods
• Grape flea beetle and climbing cutworms where injury is present

Secondary shoots and delayed regrowth may remain susceptible to feeding injury throughout the season, particularly when vines are already stressed from freeze damage. Insect feeding on recovering canopies may further reduce photosynthetic capacity and negatively affect carbohydrate storage needed for winter survival and next season’s productivity.

At the same time, reduced crop potential may allow greater flexibility in treatment thresholds in some situations. Vineyard managers should continue making management decisions based on scouting observations, pest pressure, remaining crop potential, and overall vine recovery rather than relying solely on calendar-based schedules.

Spotted lanternfly (SLF) deserves particular attention in freeze-affected vineyards. Heavy feeding by large populations can place additional stress on vines already recovering from freeze injury. Vineyards with a history of SLF pressure should continue monitoring and management efforts where warranted.

Even in vineyards with little or no fruit, maintaining healthy foliage remains important. Protecting functional canopy growth throughout the season will help support carbohydrate storage, winter hardiness, and productive growth in future years.

As vineyard recovery continues over the coming weeks, management programs will likely need to remain flexible. The full extent of freeze injury may not become apparent until secondary growth progresses and crop potential becomes clearer.

Management decisions should therefore be adjusted based on remaining crop potential, canopy recovery, vine vigor, and vineyard-specific conditions rather than standard seasonal assumptions. Different blocks within the same vineyard may require substantially different approaches depending on injury severity and remaining productivity.

Even in vineyards with severely reduced crop potential, maintaining healthy foliage and vine structure remains critical for long-term productivity. Continued attention to canopy management, nutrient decisions, disease prevention, and insect scouting will help support carbohydrate storage, winter hardiness, and productive growth in future seasons.

Growers are encouraged to continue closely monitoring vineyard recovery and adjust management programs as the season progresses.